U.S. patent number 8,234,058 [Application Number 12/283,399] was granted by the patent office on 2012-07-31 for system, module, and method for generating procedure data used in an avionics system.
This patent grant is currently assigned to Rockwell Collins, Inc.. Invention is credited to Sarah Barber, Felix B. Turcios.
United States Patent |
8,234,058 |
Barber , et al. |
July 31, 2012 |
System, module, and method for generating procedure data used in an
avionics system
Abstract
A present novel and non-trivial system, module, and method for
generating final approach, missed approach, and departure data for
use in an avionics system. A processor receives navigation data and
object data, where object data includes terrain data and/or
obstacle data. A flight path is defined, an obstacle clearance
surface is constructed and examined for object penetration, and
procedure data is generated and provided to at least one avionics
system. For approach procedures, a decision altitude data is
determined from which the procedure data is generated. A penetrated
obstacle clearance surface is allowable if a remedy exists to
address the penetration. Remedies may include the use of minimum
obstacle clearance criteria, an iterative process, a path
construction function, an existing departure procedure, and the use
of input factors to determine a real-time estimated climb
performance which could affect the climb gradient of a missed
approach path.
Inventors: |
Barber; Sarah (Cedar Rapids,
IA), Turcios; Felix B. (Cedar Rapids, IA) |
Assignee: |
Rockwell Collins, Inc. (Cedar
Rapids, IA)
|
Family
ID: |
46547673 |
Appl.
No.: |
12/283,399 |
Filed: |
September 8, 2008 |
Current U.S.
Class: |
701/120 |
Current CPC
Class: |
G08G
5/0086 (20130101); G01C 23/00 (20130101); G08G
5/0065 (20130101); G08G 5/025 (20130101) |
Current International
Class: |
G06G
7/70 (20060101); G06G 7/76 (20060101); G06F
19/00 (20110101) |
Field of
Search: |
;701/3-7,10-11,15-16,120-122 ;73/178T ;340/947-948,951,959
;244/183-188 |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Tran; Khoi
Assistant Examiner: Oh; Harry
Attorney, Agent or Firm: Suchy; Donna P. Barbieri; Daniel
M.
Claims
What is claimed is:
1. A system for generating procedure data used in an avionics
system, such system comprising: a source of navigation data; a
source of object data; and a processor, configured to receive
navigation data and object data representative of navigation
information and object information, respectively, define a flight
path, construct an obstacle clearance surface ("OCS") applicable to
the defined flight path, examine the OCS for object penetration,
where a penetrated OCS is permissible if a remedy to allow the use
of the penetrated OCS exists, adjust the penetrated OCS if a remedy
to allow the use of the penetrated OCS does not exist, generate
procedure data representative of an approach procedure, and provide
the procedure data to at least one avionics system configured to
receive the procedure data.
2. The system of claim 1, wherein the source of object data
includes a terrain database, an obstacle database, a non-database
terrain and/or obstacle acquisition system, or a combination
thereof.
3. The system of claim 1, wherein the processor is a processor of
one avionics system.
4. The system of claim 3, wherein the processor is a processor of a
flight management system, a vision system, or a display unit
system.
5. The system of claim 1, wherein the navigation data includes
runway data and waypoint data.
6. The system of claim 1, wherein the object data includes terrain
data, obstacle data, or both.
7. The system of claim 1, wherein the flight path is defined using
data associated with an existing or published flight procedure.
8. The system of claim 1, wherein an iterative process or a path
construction function is used to define the flight path, used as a
remedy to allow the use of the penetrated OCS, or both.
9. The system of claim 1, wherein minimum obstacle clearance
distance criteria is used as a remedy to allow the use of the
penetrated OCS.
10. The system of claim 1, wherein at least one avionics system
configured to receive the procedure data includes the following: a
flight management system, a vision system, or a display unit
system.
11. The system of claim 1, wherein the defined flight path is a
departure path.
12. The system of claim 11, further comprising: a source of input
factor data, and the processor is further configured to receive
input factor data, where the input factor data is used to define a
climb gradient of the departure path, used as a remedy to allow the
use of the penetrated OCS, or both.
13. The system of claim 1, wherein the defined flight path is a
final approach path, and the generation of procedure data for the
final approach path is based upon applicable decision altitude
data, where the processor is further configured to determine the
applicable decision altitude data.
14. The system of claim 13, wherein the processor is further
configured to define a missed approach path, construct a missed
approach OCS, examine the missed approach OCS for penetration,
where a penetrated missed approach OCS is permissible if a remedy
to allow the use of the penetrated missed approach OCS exists,
adjust the penetrated missed approach OCS if a remedy to allow the
use of the penetrated missed approach OCS does not exist, and
modify the applicable decision altitude data if the penetrated
missed approach OCS has been adjusted.
15. The system of claim 14, wherein the missed approach path is
defined using data associated with an existing or published
approach procedure.
16. The system of claim 14, wherein an iterative process or a path
construction function is used to define the missed approach path,
used as a remedy to allow the use of the penetrated missed approach
OCS, or both.
17. The system of claim 14, wherein minimum obstacle clearance
distance criteria is used as a remedy to allow the use of the
penetrated missed approach OCS.
18. The system of claim 14, further comprising: a source of input
factor data, and the processor is further configured to receive
input factor data, where the input factor data is used to define a
climb gradient of the missed approach path, used as a remedy to
allow the use of the penetrated missed approach OCS, or both.
19. A module for generating procedure data used in an avionics
system, such module comprising: an input communications interface
to facilitate the receiving of data from at least one data source
by a processor; the processor configured to receive navigation data
and object data representative of navigation information and object
information, respectively, define a flight path, construct an
obstacle clearance surface ("OCS") applicable to the defined flight
path, examine the OCS for object penetration, where a penetrated
OCS is permissible if a remedy to allow the use of the penetrated
OCS exists, adjust the penetrated OCS if a remedy to allow the use
of the penetrated OCS does not exist, generate procedure data
representative of an approach procedure, and provide the procedure
data to an output communications interface; and the output
communications interface to facilitate the providing of the
procedure data to at least one avionics system.
20. The module of claim 19, wherein the module is a module of one
avionics system.
21. The module of claim 20, wherein the module is a module of a
flight management system, a vision system, or a display unit
system.
22. The module of claim 19, wherein the navigation data includes
runway data and waypoint data.
23. The module of claim 19, wherein the object data includes
terrain data, obstacle data, or both.
24. The module of claim 19, wherein the flight path is defined
using data associated with an existing or published flight
procedure.
25. The module of claim 19, wherein an iterative process or a path
construction function is used to define the flight path, used as a
remedy to allow the use of the penetrated OCS, or both.
26. The module of claim 19, wherein minimum obstacle clearance
distance criteria is used as a remedy to allow the use of the
penetrated OCS.
27. The module of claim 19, wherein the defined flight path is a
departure path.
28. The module of claim 27, wherein the processor is further
configured to receive input factor data, where the input factor
data is used to define a climb gradient of the departure path, used
as a remedy to allow the use of the penetrated OCS, or both.
29. The module of claim 19, wherein the defined flight path is a
final approach path, and the generation of procedure data for the
final approach path is based upon applicable decision altitude
data, where the processor is further configured to determine the
applicable decision altitude data.
30. The module of claim 29, wherein the processor is further
configured to define a missed approach path, construct a missed
approach OCS, examine the missed approach OCS for penetration,
where a penetrated missed approach OCS is permissible if a remedy
to allow the use of the penetrated missed approach OCS exists,
adjust the penetrated missed approach OCS if a remedy to allow the
use of the penetrated missed approach OCS does not exist, and
modify the applicable decision altitude data if the missed approach
OCS has been adjusted.
31. The module of claim 30, wherein the missed approach path is
defined using data associated with an existing or published
approach procedure.
32. The module of claim 30, wherein an iterative process or a path
construction function is used to define the missed approach path,
used as a remedy to allow the use of the penetrated missed approach
OCS, or both.
33. The module of claim 30, wherein minimum obstacle clearance
distance criteria is used as a remedy to allow the use of the
penetrated missed approach OCS.
34. The module of claim 30, wherein the processor is further
configured to receive input factor data, where the input factor
data is used to define a climb gradient of the missed approach
path, used as a remedy to allow the use of the penetrated missed
approach OCS, or both.
35. A method for generating procedure data used in an avionics
system, the method comprising: performing the following steps,
where the steps are performed by a processor: receiving navigation
data and object data representative of navigation information and
object information, respectively; defining a flight path;
constructing an obstacle clearance surface ("OCS") applicable to
the defined flight path; examining the OCS for object penetration,
where a penetrated OCS is permissible if a remedy to allow the use
of the penetrated OCS exists; adjusting the penetrated OCS if a
remedy to allow the use of the penetrated OCS does not exist;
generating procedure data representative of an approach procedure;
and providing the procedure data to at least one avionics
system.
36. The method of claim 35, wherein the navigation data includes
runway data and waypoint data.
37. The method of claim 35, wherein the object data includes
terrain data, obstacle data, or both.
38. The method of claim 35, wherein the flight path is defined
using data associated with an existing or published flight
procedure.
39. The method of claim 35, wherein an iterative process or a path
construction function is used to define the flight path, used as a
remedy to allow the use of the penetrated OCS, or both.
40. The method of claim 35, wherein minimum obstacle clearance
distance criteria is used as a remedy to allow the use of the
penetrated OCS.
41. The method of claim 35, wherein the defined flight path is a
departure path.
42. The method of claim 41, further comprising: receiving input
factor data, where the input factor data is used to define a climb
gradient of the departure path, used as a remedy to allow the use
of the penetrated OCS, or both.
43. The method of claim 35, wherein the defined flight path is a
final approach path, and the generation of procedure data for the
final approach path is based upon applicable decision altitude
data.
44. The method of claim 43, further comprising: defining a missed
approach path; constructing a missed approach OCS; examining the
missed approach OCS for penetration, where a penetrated missed
approach OCS is permissible if a remedy to allow the use of the
penetrated missed approach OCS exists; adjusting the penetrated
missed approach OCS if a remedy to allow the use of the penetrated
OCS does not exist; and modifying the applicable decision altitude
data if the penetrated missed approach OCS has been adjusted.
45. The method of claim 44, wherein the missed approach path is
defined using data associated with an existing or published
approach procedure.
46. The method of claim 44, wherein an iterative process or a path
construction function is used to define the missed approach path,
used as a remedy to allow the use of the penetrated missed approach
OCS, or both.
47. The method of claim 44, wherein minimum obstacle clearance
distance criteria is used as a remedy to allow the use of the
penetrated missed approach OCS.
48. The method of claim 44, further comprising: receiving input
factor data, where the input factor data is used to define a climb
gradient of the missed approach path, used as a remedy to allow the
use of the penetrated missed approach OCS, or both.
Description
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention pertains generally to the field of aviation and the
generation of approach and departure procedure data associated with
arrival and departure paths into and out of any airport for use in
avionics equipment installed in an aircraft.
2. Description of the Related Art
An instrument approach procedure is a type of air navigation that
allows a pilot to land an aircraft in reduced visibility commonly
referred to as instrument meteorological conditions. Generally, an
approach procedure permits a pilot to descend to a decision
altitude or minimum descent altitude where a pilot is required to
see the runway environment to continue descending towards the
runway for landing or discontinue the approach by executing a
missed approach. Instrument approach procedures have evolved.
Initially, approach procedures have been developed using
ground-based navigation facilities. With the advent of a global
navigation satellite system ("GNSS") (or satellite navigation
system), approach procedures are no longer restricted to navigation
fixes or waypoints defined by ground-based facilities. Instead,
waypoints can be established using the latitude/longitude
coordinate system. With the advent of the GNSS, approach procedures
have been created by aviation-governing authorities using waypoints
as part of area navigation ("RNAV").
In addition to instrument approach procedure, a departure procedure
is a type of air navigation that allows a pilot to take-off an
aircraft following a prescribed procedure. A published departure
procedure provides flight procedures for an aircraft to follow to
ensure either an obstacle-free departure path or to permit the
aircraft to follow a defined route required by ATC for air traffic
flow management.
The design of approach and departure procedures includes the
construction of an obstacle clearance surface ("OCS"). An OCS is
constructed to provide the pilot assurance that the approach and
departure procedure is free from objects such as obstacles and
terrain. With the use of design criteria, an OCS may be constructed
and examined for objects penetrating the surface of the OCS. If an
object penetrates that OCS, then adjustments will have to be made
to the OCS. In an area of mountainous terrain, this could
significantly impact the decision altitude or minimum descent
altitude to where a pilot may descend the aircraft; also, it could
significantly impact the ability for a pilot to take-off from a
runway in poor visibility conditions. Current approach and
departure procedure design criteria do not provide for remedies
which allow the surface of an OCS to be penetrated.
BRIEF SUMMARY OF THE INVENTION
A present novel and non-trivial system, module, and method for
generating final approach data, missed approach data, and departure
data for use in an avionics system, where the generation of such
data allows for the use of a penetrated OCS and possible lower
altitudes and/or climb gradients. Approach and departure procedure
data that is generated may be provided to at least one avionics
system that may include a FMS, display unit system, and/or a vision
system. As embodied herein, procedure data may be used, in whole or
in part, as a basis for forming a flight route corridor image on a
display unit, where the display of a flight route corridor includes
the display of objects such as terrain and obstacles that penetrate
an obstacle clearance surface or objects that may not meet a
minimum obstacle clearance distance. A system, module, and/or
method for constructing a flight route corridor image is described
in a U.S. patent application Ser. No. 12/283,400 entitled "System,
Module, and Method for Generating an Image of a Flight Route
Corridor on a Display Unit," which is incorporated by reference in
its entirety.
In one embodiment, a system is disclosed for generating departure
and approach data for use in an avionics system. The system
comprises a source of navigation data, a source of object data
where an object may be terrain and/or obstacles, a processor, and
an avionics system to receive the generated approach data. After
receiving the navigation data and object data, an approach or
departure path may be defined by the processor; as embodied herein,
the path may include a glide path of a final approach procedure
and/or a climb path of a missed approach path or departure path.
Then, an obstacle clearance surface ("OCS") may be constructed and
examined for object penetration using design criteria appropriate
for the procedure. If penetration is found to exist, the OCS may be
adjusted if there is no remedy which will allow for the use of the
penetrated OCS. Then, procedure data is generated and provided to
at least one avionics system that may include a FMS, display unit
system, and/or a vision system. For approach procedures, decision
altitude data is determined and included in the generation of
procedure data.
As embodied herein, remedies may include the use of minimum
obstacle clearance criteria, an iterative process, a path
construction function, an existing departure procedure, and the use
of input factors to determine a real-time estimated climb
performance which could affect the climb gradient of a missed
approach path.
In another embodiment, a module is disclosed for generating
approach and departure data for use in an avionics system. The
module comprises an input communications interface, a processor,
and an output communications interface. The input communications
interface facilitates the receipt of data, and the output
communications interface facilitates the providing of data. As
discussed above, the processor may receive navigation data and
object data; define an approach or departure path; and construct,
examine, and adjust an OCS if no remedy exists to allow the use of
a penetrated OCS. As embodied herein, the approach path may be
associated with a final approach procedure or a missed approach
procedure, and a departure path may be associated with a departure
procedure. As further embodied herein, the processor may determine
the applicability of the remedies discussed above for a penetrated
OCS. Then, the processor may generate approach or departure
procedure data, whereby such data is provided through the output
communications interface to at least one avionics system. For
approach procedures, decision altitude data is determined and
included in the generation of procedure data, the processor may
also determine applicable decision altitude data.
In another embodiment, a method is disclosed for generating
approach and departure data for use in an avionics system. The
method comprises receiving navigation data and object data;
defining a flight path; and constructing an OCS, and adjusting an
OCS if no remedy exists to allow the use of a penetrated OCS. Then,
the method comprises generating of approach or departure procedure
data and providing the approach or departure procedure data to at
least one avionics system. For approach paths, the method includes
determining of applicable decision altitude data. As embodied
herein, the approach path may be associated with a final approach
procedure or a missed approach procedure, and remedies exist to
address the allowable use of a penetrated OCS.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 depicts a block diagram of a system for generating approach
and departure data for use in an avionics system.
The drawings of FIG. 2 depict some of the reference points and
definitions associated with the design of approach procedures.
The drawings of FIG. 3 illustrate a final approach OCS associated
with an LPV procedure.
The drawings of FIG. 4 provide formulas associated with a LPV final
approach OCS.
FIG. 5 illustrates a missed approach OCS associated with an LPV
approach.
FIG. 6 provides formulas associated with an LPV missed approach
OCS.
The drawings of FIG. 7 illustrate a final approach OCS associated
with an LNAV/VNAV procedure.
FIG. 8 provides formulas associated with an LNAV/VNAV final
approach OCS.
The drawings of FIG. 9 illustrate a missed approach OCS associated
with an LNAV/VNAV approach.
FIG. 10 provides formulas associated with an LNAV/VNAV missed
approach OCS.
FIG. 11 illustrates a published approach procedure.
FIG. 12 illustrates a second published approach procedure.
FIG. 13 illustrates a published obstacle departure procedure.
FIG. 14 depicts a flowchart of a method for generating final
approach data for use in an avionics system.
FIG. 15 depicts a flowchart of a method for generating missed
approach data for use in an avionics system.
FIG. 16 depicts a flowchart of a method for generating departure
data for use in an avionics system.
DETAILED DESCRIPTION OF THE INVENTION
In the following description, several specific details are
presented to provide a thorough understanding of the embodiments of
the invention. One skilled in the relevant art will recognize,
however, that the invention can be practiced without one or more of
the specific details, or in combination with other components, etc.
In other instances, well-known implementations or operations are
not shown or described in detail to avoid obscuring aspects of
various embodiments of the invention.
FIG. 1 depicts a block diagram of an aircraft procedure generation
system 100 suitable for implementation of the techniques described
herein. The aircraft procedure generation system 100 of an
embodiment of FIG. 1 may include navigation system 110, object data
source 130, flight navigation database 140, input factors 150, a
processor 170, and display units 180.
In an embodiment of FIG. 1, a navigation system 110 comprises the
system or systems that could provide navigation data information in
an aircraft. It should be noted that data, as embodied herein for
any source or system in an aircraft including a navigation system,
could be comprised of any analog or digital signal, either discrete
or continuous, which could contain information. As embodied herein,
aircraft could mean any vehicle which is able to fly through the
air or atmosphere including, but not limited to, lighter than air
vehicles and heavier than air vehicles, wherein the latter may
include fixed-wing and rotary-wing vehicles. A navigation system
110 may include, but is not limited to, an air/data system, an
attitude heading reference system, an inertial guidance system (or
inertial reference system), a global navigation satellite system
("GNSS") (or satellite navigation system), and a flight management
system ("FMS"), all of which are known to those skilled in the art.
For the purposes of the embodiments herein, a radio altimeter
system may be included in the navigation system 110; a radio
altimeter system is known to those skilled in the art for
determining the altitude above the surface over which the aircraft
is currently operating. As embodied herein, a navigation system 110
could provide navigation information including, but not limited to,
geographic position 112, altitude 114, attitude 116, speed 118,
vertical speed 120, heading 122, radio altitude 124, and data
quality 128 to a processor 170 for subsequent processing as
discussed herein.
Navigation data quality 128 may include, but is not limited to,
accuracy, uncertainty, integrity, and validity for data provided by
a navigation system 110. As embodied herein, aircraft position
comprises geographic position (e.g., latitude and longitude
coordinates) and altitude, and direction may be derived from either
geographic position, aircraft position, or both. As embodied
herein, aircraft orientation may include pitch, roll, and/or yaw
information related to the attitude of the aircraft.
In an embodiment of FIG. 1, an object data source 130 may include,
but is not limited to, a terrain database 132, obstacle database
134, and other aircraft systems 136, or any combination thereof. As
embodied herein, object data may include terrain data, obstacle
data, or both. An object data source 130 could comprise any source
of terrain data, obstacle data, other manmade or natural features,
geopolitical boundaries, or any combination thereof. Obstacles may
include, but are not limited to, towers, buildings, poles, wires,
other manmade structures, and foliage.
A terrain database 132 may be any database used to store terrain
data contained in digital elevation models ("DEM"). Generally, the
terrain data of a DEM is stored as grids composed of cells, and
each grid or cell represents an area of terrain. A grid or cell may
be of various shapes. For example, a grid or cell may be defined in
arc-seconds of latitude and longitude, or may be rectangular,
square, hexagonal, or circular. A grid or cell may also be of
differing resolutions. For instance, the U.S. Geological Society
developed GTOPO30, a global DEM which may provide 30 arc-seconds
(approximately 900 meters) resolution. On the other hand, the Space
Shuttle Endeavour in February 2000 acquired elevation data known as
Shuttle Radar Topography Mission ("SRTM") terrain elevation data
which may provide generally one arc-second (or approximately 30
meters) resolution, providing much greater detail than that
provided with the GTOPO30 data set. At the present time,
resolutions of one-arc second for SRTM terrain data are available
for areas over the United States; for all other locations,
resolutions of three arc-seconds (approx. 90 meters) are available.
In addition to these public sources of terrain data, there are
military and private sources of terrain data. Various vendors and
designers of avionics equipment have developed databases that have
been, for all intents and purposes, proprietary in nature.
It should be noted that data contained in any database discussed
herein including a terrain database 132, obstacle database 134, and
navigation database 140 may be stored in a digital memory storage
device or computer-readable media including, but not limited to,
RAM, ROM, CD, DVD, hard disk drive, diskette, solid-state memory,
PCMCIA or PC Card, secure digital cards, and compact flash cards.
Data contained in such databases could be loaded while an aircraft
is on the ground or in flight. Data contained in such databases
could be provided manually or automatically through an aircraft
system capable of receiving and/or providing such manual or
automated data. Data contained in such databases could be temporary
in nature; for example, data representative of a temporary obstacle
could be stored in an obstacle database 134, and a temporary runway
closure could be stored in a navigation database 140. Any database
used in the embodiments disclosed herein may be a stand-alone
database or a combination of databases. For example, a terrain
database 132 may be associated with a terrain awareness and warning
system ("TAWS") only. In an alternative embodiment, terrain data
could be stored in or combined with an airport database, airspace
database, or with a database used by any other aircraft system
including, but not limited to, an FMS, or an airspace awareness and
warning system ("AAWS").
Although other aircraft systems 136 could employ terrain databases
132, such systems could also be a source of terrain data provided
to a processor 170. For example, a synthetic vision system ("SVS")
may employ a terrain database and/or obstacle database to generate
terrain image data. Here, the terrain database and/or obstacle
database that is part of an SVS could be the source of object data.
Alternatively, the SVS could provide a processor 170 with terrain
data in the form of terrain image data.
In another alternative, non-database terrain and/or obstacle
acquisition system. For example, a radar-based TAWS system could
provide real-time terrain and/or obstacle data which could be
employed, like any other data source, in the real-time generation
of approach and departure procedure data. Moreover, a non-database
source of object data could be used to as a second source of such
data that may be used in conjunction with or used as a source of
redundant information that may be provided along with data stored
in a database. Other examples of other aircraft systems 136 which
could comprise sources of terrain data include, but are not limited
to, an AAWS. As embodied herein, a terrain database 132, an
obstacle database 134, and/or other aircraft systems 136 could
provide data representative of objects to a processor 170 for
subsequent processing as discussed herein.
A navigation database 140 could contain data associated with
ground-based navigational aids, waypoints, holding patterns,
airways, airports, heliports, instrument departure procedures,
instrument arrival procedures, instrument approach procedures,
runways, precision approach aids, company routes, airport
communications, localizer and airway markers, restrictive airspace,
airport sector altitudes, enroute airways restrictions, enroute
communications, preferred routes, controlled airspace, geographical
references, arrival and/or departure flight planning, path point
records, GNSS Landing Systems. Such navigation database 140 could
be provided by an aircraft system such as, but not limited to, an
FMS, a system known to those skilled in the art.
Data contained in a navigation database 140 could be used in the
construction of approach and departure procedures as disclosed
herein. Generally, an aviation regulatory authority or organization
possesses the authority of designing and designating instrument
approach and departure procedures. In the United States, the
Federal Aviation Administration ("FAA") establishes and provides
definitions and ascertainable dimensions of instrument approach and
departure procedures. For instance, FAA Order 8260.3B entitled
"United States Standard for Terminal Instrument Procedures (TERPS)"
dated May 15, 2002 provides criteria used to formulate, review,
approve, and publish procedures for instrument approach and
departure of aircraft to and from civil and military airports.
Also, FAA Order 8260.54A entitled "The United States Standard for
Area Navigation (RNAV)" provides criteria for obstacle clearance
evaluation of RNAV approach procedures, e.g., Localizer Performance
with Vertical Navigation ("LPV"), Lateral Navigation ("LNAV"),
Lateral Navigation/Vertical Navigation ("LNAV/VNAV"), and Localizer
Performance ("LP"). The criteria in FAA Order 8260.54A support
adding an instrument approach system (ILS) line of minimum to an
RNAV (GPS) approach procedure using LPV construction criteria at
runways served by an instrument landing system. At the time of this
writing, both Orders may be obtained on the Internet at
http://www.faa.gov/about/office_org/headquarters_offices/avs/offices/afs/-
afs400/afs420/policies_guidance/orders/.
The discussion herein may be drawn to these FAA standards for the
purpose of simplifying the illustration and discussion only;
however, the embodiments are neither limited nor restricted to the
design and designation criteria of instrument approach or departure
procedures employed in the United States or those with governing
oversight of the FAA. It is known to those skilled in the art that
aviation governing authorities throughout the world may develop or
may have developed criteria unique to their respective
jurisdictions which may or may not employ similar instrument
approach or departure procedure criteria, and end users of
navigational data could develop criteria directed to unique
operational requirements that may or may not require special
equipment or authorization. The embodiments disclosed herein could
include any procedure developed from at least one ascertainable fix
and obstacle clearance evaluation criteria.
The drawings of FIG. 2 depict some of the reference points and
definitions associated with a runway 202 that may be employed by
the FAA as approach construction criteria used in the design of
instrument approach procedures. It should be noted that although
the detailed discussion herein will be drawn towards final and
missed approach procedures, those skilled in the art understand
that other reference points and definitions associated with a
runway may be employed by the FAA as departure construction
criteria used in the design of departure procedures. The
embodiments herein include any procedure that may use reference
points and definitions employed as construction criteria.
Data representative of these points and definitions for one or more
runways could be contained in a navigation database 140. A runway
Landing Threshold Point ("LTP") 204 (which could also be called a
runway threshold point) may be a three dimensional point at an
intersection of the runway centerline 206 and the runway threshold
("RWT") 208; the direction of a runway centerline 206 from an LTP
204 may be measured in reference to magnetic north using a magnetic
bearing. In one embodiment, an LTP 204 could be defined using
latitude, longitude, and elevation derived from government sources.
In another embodiment, a geoid height could be included in
definition, where a geoid could be considered to be an
equipotential surface that is everywhere normal to the direction of
gravity and would coincide with the mean ocean surface of the
Earth, if the oceans were in equilibrium, at rest, and extended
through the continents. The surface of a geoid may be approximated
using a mathematically-defined reference ellipsoid employed in a
geodetic system. The height of a geoid ("GH") may be measured
relative to the ellipsoid, and it may be positive if it is above
the reference ellipsoid and negative if it is below.
Geodetics or geodesy is a scientific discipline dealing with the
measurement and representation of the Earth. An example of a
geodetic system, provided for the purpose of illustration and not
limitation, is a World Geodetic System ("WGS"). A WGS could be
used, for example, in a GNSS to provide a frame of reference or
coordinate system of the Earth. WGS's have evolved with past
refinements made possible due to additional global data from
precise and accurate measurements and will likely further evolve
with future refinements. Those skilled in the art can appreciate
the adaptability of future refinements of the WGS or any other
geodetic system to the embodiments disclosed.
A glidepath angle ("GPA") 210 may be the angle of a specified final
approach descent path 212 (or glidepath) to be flown by an aircraft
214 relative to an Approach Surface Base Line ("ASBL") 216 at the
RWT 208, where the ASBL 216 may be considered as a horizontal line
tangent to the Earth. A Threshold Crossing Height ("TCH") 218 may
be the height of the GPA 210 above the LTP 204. A Flight Path
Control Point ("FPCP") 220 may be an imaginary point above the LTP
204 at the TCH 218 from which the glidepath mathematically
emanates.
A Flight Path Alignment Point ("FPAP") 222 or 224 may be a
three-dimensional point used in conjunction with a LTP 204 and the
geometric center of a WGS reference ellipsoid to define a vertical
plane containing a final approach course of a final approach
descent path 212. As shown in FIG. 2A, an FPAP 222 could be located
at the departure end of the runway 202 that is opposite of the RWT
208, or it could be located at a different location. As shown in
FIG. 2B, an FPAP 224 and a final approach course 212 may be offset
from a runway centerline 206, and where such offset exists, a
Fictitious Threshold Point ("FTP") 228 could be used as an
equivalent of a LTP 204, where the FTP 228 may be located at an
intersection of a final approach course 212 and a line
perpendicular to it passing through the LTP 204; the elevation of
an FTP 228 could be the same as an LTP 204, and a FPCP may be an
imaginary point above the FTP 228 at the TCH from which the
glidepath mathematically emanates. The angle of offset 226 may be
the angle formed between a final approach course 230 and an
extended runway centerline 232 having the same direction or
magnetic bearing as runway centerline 206. A Ground Point of
Intercept ("GPI") 234 may be a point in the vertical plane where
the final approach descent path 212 intercepts the ASBL 216.
Data representative of the points and definitions depicted in the
drawings of FIG. 2 and associated with one or more runways could be
contained in a navigation database 140. Some or all of the
reference points and definitions could be used as approach
construction criteria in the design of instrument approach
procedures including criteria specified for obstacle clearance
evaluation of Area Navigation ("RNAV") approach procedures
including, but not limited to, Localizer Performance with Vertical
Guidance ("LPV"), Lateral Navigation/Vertical Navigation
("LNAV/VNAV"), Localizer Performance ("LP"), and Lateral Navigation
("LNAV"). Typically, LPV and LNAV/VNAV approach procedures provide
vertically guided procedures, and LP and LNAV approach procedures
provide non-vertically guided procedures. The application of
approach construction criteria to LPV and LNAV/VNAV approach
procedures will be discussed in detail below, and even though the
remaining discussion herein will be drawn to the LPV and LNAV/VNAV
approach procedures, the embodiments herein could be applied to
other construction criteria of other approach procedures including,
but not limited to, the LP and LNAV approach procedures.
Returning to FIG. 1, input factors 150 are determining factors
which may be used to determine one or more climb gradients based
upon climb performance as disclosed in detail below. Input factors
150 may be provided by a plurality of aircraft systems or
components thereof. Input factors 150 could include real-time
system or sensor data, signal input from a plurality of aircraft
systems or sensors, and information from any database or source. As
embodied herein, an input factor 150 could provide data or a signal
of any form containing information that may be provided to and
received by a processor 170.
As embodied herein, input factors 150 could include those inputs
defined above as being part of the navigation system 110 (e.g.,
geographic position 112, altitude 114, attitude 116, speed 118,
vertical speed 120, heading 122, radio altitude 124, and navigation
data quality 126). Moreover, any input provided by a navigation
system 110 could be considered an input factor for the purposes of
the embodiments herein. In other words, a navigation system 110 may
be considered as providing a subset of input factors 150. The
presentation of the specific inputs from navigation system 110
should not be construed as an exclusion or limitation to input
factors 150. As embodied herein, input factors 150 may include
information from any data or information source available to a
processor 170 including, but not limited to, an object data source
130 and a runway data source 140. In other words, an object data
source 130 and a runway data source 140 may be considered as
sources providing a subset of input factors 150. The presentation
of an object data source and a runway data source as separate item
numbers 130 and 140 should not be construed as an exclusion or
limitation to input factors 150.
In an embodiment herein, input factors 150 may be selected by a
manufacturer or end user as a determining factor for one or more
climb criteria used in an equation that could define climb
performance. Climb performance may be defined by an equation
containing one or more selected climb criteria, each of which may
be comprised of one or more input factors 150.
In another embodiment herein, input factors 150 may be selected by
a manufacturer or end user for one or more climb criteria used in
an equation that could define climb performance to determine climb
gradient. As embodied herein, climb performance could provide the
basis for determining a climb gradient. A climb gradient may be
defined by at least one equation containing one or more selected
climb criteria.
When included in an equation, data representative of input factors
150 may be acquired by or through aircraft systems and sensors as
discussed above and provided as input to a processor 170. When
received, the processor 170 may process the data in accordance with
a climb performance algorithm that could contain the equation or
equations defining a climb performance. As a result, the processor
170 may determine a climb gradient based upon the application of
the real-time dynamic or static input factors 150.
One or more climb performances may be defined using one or more
selected climb criteria, each of which may be dependent on one or
more input factors 150. The application of such climb criteria and
input factors 150 by a processor 170 may determine a climb gradient
and/or climb distance representative of real-time predictable and
achievable aircraft performance using input factors 150. Although a
manufacturer or end user may define a climb performance using one
climb criterion such as an aircraft's maximum gross weight (as will
be discussed below in detail) that may be independent of input
factors 150, the advantages and benefits of the embodiments herein
exploit the ability of a processor 170 to receive a plurality of
available input factors 150, apply them to a climb performance
defined and contained in an algorithm, and determine a climb
gradient and/or climb distance unique to actual conditions of
flight operations as measured by the values of the input factors
150.
To provide a simple example of how input factors 150 may be used in
the embodiments herein, suppose a climb performance comprises
meteorological or environmental criteria such as pressure altitude,
temperature, wind, and weight. Those skilled in the art understand
that a climb gradient may be affected by a plurality of factors
including, but not limited to, pressure altitude, temperature,
humidity, wind, and weight. Here, determining factors representing
altitude 114, temperature 152, barometric pressure 153, dew point
154, wind direction 155, wind speed 156, and current weight 157 may
be provided as input factors 150 to processor 170 for subsequent
processing in accordance with the climb criteria that defines the
climb performance. A processor 170 is able to define a climb
gradient that is real-time because it is based upon input factors
150.
In the following paragraphs, other examples of climb criteria and
performance factors are provided to illustrate the ability with
which a manufacturer or end user may define a climb gradient as
embodied herein. These illustrations are intended to provide
exemplary climb criteria and performance factors that may be used
in a procedure generation system 100, and are not intended to
provide a limitation to the embodiments discussed herein in any
way, shape, or form.
As noted above, input factors 150 may include some of those inputs
provided to a processor 170 by a navigation system 110, even though
they are not enumerated under item 150 of FIG. 1; input factors
that could affect the performance of the aircraft may include some
inputs that are provided by any aircraft system other than a
navigation system 110. As embodied herein, one or more input
factors 150 could be included in the computation of another input
factor. For instance, wind direction 155 and wind speed 156 have
been considered in a computation of speed 118, and barometric
pressure 153 could have been considered in a computation of
altitude 114. In such instances, a processor 170 may be programmed
to accept only one of these factors.
In another example, a climb performance could include weight and
balance climb criteria. If so, input factors 150 could include, but
are not limited to, data representative of aircraft empty weight
157, center of gravity ("CG") 158, weight of fuel 159, weight of
cargo 160, weight of passengers 161, and number of passengers and
crew 162 (for which a standard weight can be applied). In another
example, a climb performance could include aircraft climb
configuration and system climb criteria. If so, input factors 150
could include, but are not limited to, data representative of an
aircraft's flaps and slats 163, spoilers 164, speed brake 165, and
landing gear 166 configurations. In another example, a climb
performance could include engine performance climb criteria. If so,
input factors 150 could include, but are not limited to, data
representative of engine performance or status 167 or available
thrust. In another example, the determination of climb performance
could include an assumption that one engine of a multi-engine
aircraft is inoperative.
A processor 170 may be any electronic data processing unit which
executes software or source code stored, permanently or
temporarily, in a digital memory storage device or
computer-readable media (not depicted herein) including, but not
limited to, RAM, ROM, CD, DVD, hard disk drive, diskette,
solid-state memory, PCMCIA or PC Card, secure digital cards, and
compact flash cards. A processor 170 may be driven by the execution
of software or source code containing algorithms developed for the
specific functions embodied herein. Common examples of electronic
data processing units are microprocessors, Digital Signal
Processors (DSPs), Programmable Logic Devices (PLDs), Programmable
Gate Arrays (PGAs), and signal generators; however, for the
embodiments herein, the term processor is not limited to such
processing units and its meaning is not intended to be construed
narrowly. For instance, a processor could also consist of more than
one electronic data processing units. As embodied herein, a
processor 170 could be a processor(s) used by or in conjunction
with any other system of the aircraft including, but not limited
to, a processor(s) associated with a navigation system, an FMS, a
TAWS, a vision system, or any combination thereof.
A processor 170 may receive as input data representative of
information obtained from various systems and/or sources including,
but not limited to, navigation system 110, object data source 130,
a flight navigation database 140, and input factors 150. A
processor 170 may be electronically coupled to systems and/or
sources to facilitate the receipt of input data; as embodied
herein, operatively coupled may be considered as interchangeable
with electronically coupled. A processor 170 may provide output
data to various systems and/or units including, but not limited to,
display units 180, and a crew alerting system 190. A processor 170
may be electronically coupled to systems and/or units to facilitate
the providing of output data representative of a procedure. It is
not necessary that a direct connection be made; instead, such
receipt of input data and the providing of output data could be
provided through a data bus or through a wireless network.
Display units 180 may include, but are not limited to, HDD units
182 units and HUD 188 units. As embodied herein, a display unit
which may display approach or departure information. Display units
180 may display image from data produced by one or more vision
systems such as, but not limited to, an SVS, an enhanced vision
system ("EVS"), or a combined SVS-EVS. HDD units 182 are typically
units mounted to an aircraft's flight instrument panel located in
front of a pilot and below the windshield and the pilot's field of
vision. As embodied herein, tactical flight information displayed
on a tactical display unit 184 could be information relevant to the
instant or immediate control of the aircraft, whether the aircraft
is in flight or on the ground. A tactical display unit 184 could
display the same information found on a primary flight display
("PFD"), such as "basic T" information (i.e., airspeed, attitude,
altitude, and heading). Although it may provide the same
information as that of a PFD, tactical display unit 164 may also
display a plurality of indications or information including, but
not limited to, flight route, selected magnetic heading, actual
magnetic track, selected airspeeds, selected altitudes, altitude
barometric correction setting, vertical speed displays, flight path
angle and drift angles, flight director commands, limiting and
operational speeds, mach number, radio altitude and decision
height, final approach trajectory deviations, and marker
indications. A tactical display unit 164 is designed to provide
flexible configurations which may be tailored to the desired
configuration specified by a buyer or user of the aircraft.
As embodied herein, a tactical unit display 164 may display an
image of a flight route corridor, where a flight route could be the
same as a flight path as discussed herein including, but not
limited to, a glidepath and/or climb path. The display of a flight
route corridor could include the display of one or more objects
penetrating an obstacle clearance surface or objects that would not
meet a minimum obstacle clearance distance, both of which are
discussed below in detail. Approach or departure procedure data
generated by the embodiments disclosed herein could be used, in
part or in whole, in the generation of a flight route corridor
image. A system, module, and/or method for constructing an flight
route corridor image is described in a U.S. patent application Ser.
No. 12/283,400 entitled "System, Module, and Method for Generating
an Image of a Flight Route Corridor on a Display Unit," which is
incorporated by reference in its entirety.
A strategic display unit 186 could be a unit which presents
information to the crew relative to the intended future state(s) of
the aircraft (e.g. intended location in space at specified times)
along with information providing contextual information to the crew
(e.g. terrain, navigation aids, geopolitical boundaries, airspace
boundaries, etc.) about such state(s). One example of such display
unit is commonly referred to as a Navigation Display. In some
configurations, the strategic display unit could be part of an
Electronic Flight Information System ("EFIS"). On these systems,
terrain information may be displayed simultaneously with
information of other systems. In one embodiment herein, terrain
information may be displayed simultaneously with weather
information with no loss or a negligible loss of displayed
information.
As embodied herein, display units 180 may include a vision system
(not shown) which generates an image data set which represents the
image displayed on a display unit. Vision systems include, but are
not limited to, SVS, EVS, combined SVS-EVS, or combination thereof.
As embodied herein, approach procedure or departure data could be
included, in part or in whole, in the generation of an image data
set. As embodied herein, the image represented the image data set
could include an image of a flight route corridor.
It should be noted that the following disclosure will discuss in
detail the construction of approach procedures and provide examples
demonstrating the application of procedure design criteria to
construct obstacle clearance surfaces and examine them for object
penetration. Although the discussion will be drawn to the final and
missed approach procedures of two types of procedures developed by
the FAA (the LPV and LNAV/VNAV procedures), the embodiments herein
are not limited to approach procedures. The embodiments herein
include departure procedures associated with a flight path from
which an obstacle clearance surface may be constructed and examined
for object penetration.
The drawings of FIG. 3 illustrate an obstacle clearance surface
("OCS") that could be applicable to a final approach segment of a
precision final approach or an LPV approach (not drawn to scale).
FIG. 3A presents a plan view and profile view of an OCS having a
slope 302 and located below a glidepath 304 extending from an FPCP
306 and having a GPA 308 measured in terms of .theta.; as stated
above, an FPCP may be an imaginary point above the LTP 310 (or an
FTP) at the TCH from which the glidepath mathematically emanates.
As shown by formula 4-1 in FIG. 4A, slope S may be measured as run
over rise and may be determined using approach design criteria.
Generally, an OCS may be an upward or downward sloping surface used
for object evaluation where the flight path is climbing or
descending and may be comprised of more than one surface; as shown
in the drawings of FIG. 3, an OCS may be comprised of a plurality
of surfaces: a W surface ("W OCS"), an X surface ("X OCS"), and a Y
surface ("Y OCS"). The separation between the OCS and a vertical
path angle such as GPA 308 defines the minimum object clearance
("ROC") required for any given point. An OCS may be primarily
comprised of primary surfaces W OCS and X OCS, and a transitional
surface Y OCS.
The origination of an OCS may be determined using a point of
reference. As embodied in FIG. 3A, an LTP 310 of a runway 312 (or
FTP if applicable) could serve as a reference point from which the
origin or beginning of an OCS, i.e., the OCS origin 314, may be
determined. An OCS origin 314 may be defined as being a fixed
distance D(o) 316 from an LTP 310. As depicted in FIG. 3A, the OCS
could begin at D(o)=200' from the LTP 310 measured along the final
approach course centerline 318 and could extend to a second
position located at a fixed distance from an OCS origin 314. As
depicted in FIG. 3A, the second position is located at the fixed
distance of 50,000 feet from the OCS origin 314. Alternatively, the
second position could be a Precision Final Approach Fix ("PFAF")
(not shown) located at a distance D(PFAF) and determined using
elevation LTP(elev) of the LTP 310 and the radius r of the Earth
could serve as a reference datum in approach design criteria. As
shown by formula 4-2 in FIG. 4A, D(PFAF) may be determined as a
function of the LTP(elev), r, .theta., TCH, and alt(min), a minimum
intermediate segment altitude that may be determined using approach
design criteria.
The origination of an OCS slope 320 could begin at an OCS origin
314, or as depicted in FIG. 3A, at another position located a
distance "d" from the OCS origin 314. OCS slope origin 320 may be
pushed back or away from the LTP 310 a distance "d" from the OCS
origin 314 if, for example, a GPI and the RWT are relatively near
each other. By pushing back the OCS slope origin 320, objects close
to the RWT could end up penetrating the OCS that otherwise would
not. Distance "d" may be determined using approach design criteria.
As shown by formula 4-3 of FIG. 4A, "d" may be determined as a
function of GPI (i.e., TCH and .theta.), where TCH may be based
upon an approximate glidepath-to-wheel height of an aircraft; for
example, a recommended TCH value of 40 feet could be assigned to a
height group comprising of general aviation aircraft, and a
recommended TCH value of 55 feet could be assigned to a height
group comprising large aircraft such as a B-747 or A-380. Besides
recommended TCH values, a TCH could have a range of values between
a minimum allowable TCH and a maximum allowable TCH.
As an OCS extends away from the runway 312, the width of the OCS
may expand outwardly from a final approach course centerline 318,
i.e., the lateral boundaries of the OCS become wider. As shown in
FIG. 3A, the outward expansion could be linear. FIGS. 3B and 3C
depict cross-sections of an OCS at an OCS origin 314 located 200
feet from an LTP 310 and a second position located 50,000 feet from
the OCS origin 314, respectively. A comparison between FIGS. 3B and
3C illustrates a difference in widths not only of an OCS between
the two locations but also a difference in widths between the
surfaces W OCS, X OCS, and Y OCS up through the second position
located 50,000 feet from the OCS origin 314.
The outer boundaries of the W OCS, X OCS, and Y OCS may be
determined using approach design criteria. For example,
perpendiculars extending from points along the final approach
course centerline 318 may be used to locate corresponding points
along each of the boundaries. As shown by formulas 4-4, 4-5, and
4-6 in FIG. 4A, perpendicular distances W(w), W(x), and W(y)
between a point on the course centerline and respective points on
the W OCS boundary, X OCS boundary, and Y OCS boundary may be
determined as a function of distance D, where D may be the distance
between a LTP or FTP and to a point on the course centerline.
Application of formulas 4-4, 4-5, and 4-6 results in the distances
shown in FIG. 3B. The outer boundaries of the W surface, X surface,
and Y surface at the OCS origin 314 are 400 feet, 700 feet
(400'+300'), and 1,000 feet (400'+300'+300'), respectively, and
perpendicular to the centerline of the final approach course
located at the midpoint of the W surface. Likewise, as shown by the
distances shown in FIG. 3C, the outer boundaries of the W surface,
X surface, and Y surface at a position 50,000 feet from the OCS
origin 314 are 2,200 feet, 6,076 feet, and 8,576 feet (i.e.,
2,200'+6,076'), respectively, and perpendicular to the centerline
of the final approach course located at the midpoint of the W
surface.
An OCS may comprise one or more surfaces between laterally sloping
surfaces. As indicated in both FIGS. 3B and 3C, the outward run
over rise of X OCS is 4:1 from the outer boundary of the W OCS, and
the outward run over rise of Y OCS is 7:1 from the outer boundary
of the X OCS.
Besides length and width of the OCS, the height of any point on the
OCS may be determined by using approach design criteria. As shown
by formula 4-7 in FIG. 4A, the height Z(w) of the W OCS above a
reference datum such as an ASBL may be determined as a function of
D, d, and S.
The heights of any point on the X OCS and the Y OCS may also be
determined using approach design criteria. Height Z(x) of a point
on the X OCS may be determined by adding Z(w) to the value of the
rise of the X OCS to the point, which may be determined from a
perpendicular extending horizontally from the final approach course
centerline 318 to a point below the point on the X OCS. As shown by
formula 4-8 in FIG. 4A, height Z(x) may be determined as a function
of Z(w), W(w), and D(xp), where D(xp) is the perpendicular distance
between the course centerline and a point below the point on the X
OCS.
Similarly, height Z(y) of a point on the Y OCS may be determined by
adding Z(w) and Z(x) to the rise of the Y OCS to the point, which
may be determined from a perpendicular extending horizontally from
the final approach course centerline 318 to a point below the point
on the Y OCS. As shown by formula 4-9 in FIG. 4A, height Z(y) may
be determined as a function of Z(x), W(x), W(w), and D(yp), where
D(yp) is the perpendicular distance between the course centerline
and a point below the point on the Y OCS.
The final approach course centerline 318 of the final approach
course of the OCS depicted in FIG. 3A is shown as being aligned
with an extended runway centerline; however, as depicted in FIG.
2B, the final approach course 230 may be offset 226 from an
extended runway centerline 232. If an offset is used, approach
design criteria could impose limits; for example, an LPV approach
may be limited to an angle no greater than 3 degrees. Also, if an
offset is used, design criteria impose a distance restriction for
the intersection of the final approach course centerline 318 and
the extended runway centerline; for example, an LPV approach may
require the final approach course centerline 318 to intersect the
extended runway centerline at a point 1,100 feet to 1,200 feet
inside a decision altitude point (which will be discussed in detail
below). In addition, if an offset is used, design criteria may
require a higher minimum height above the threshold (which will be
discussed in detail below).
In the discussion above, a reference datum such as an ASBL could
have been used in the determination of heights Z(w), Z(x), and
Z(y). Alternatively, heights of points on the W surface, X surface,
and Y surface may be expressed as elevations above mean sea level,
and the elevation LTP(elev) of the LTP 310 and the radius r of the
Earth could serve as a reference datum in approach design criteria.
As shown by formula 4-10 shown in FIG. 4A, the elevation Z(we) of
the W OCS may be determined as a function of LTP(elev), .theta., d,
r, and D. After determining Z(we), the elevation Z(xe) of the X OCS
and the elevation Z(ye) of the Y OCS could be found by adding Z(we)
to Z(x) and Z(y), respectively.
After an OCS has been created for a specific runway, the OCS may be
examined for surface object penetration. A known height of an
object could be compared with the height of either the W Surface, X
Surface, or Y Surface above it, and if the height of the object is
greater than Z(w), Z(x), or Z(y), respectively, then the object has
penetrated the OCS. Similarly, a known elevation of an object could
be compared with the elevation of either the W Surface, X Surface,
or Y Surface above it, and if the elevation of the object is
greater than Z(we), Z(xe), or Z(ye), respectively, then the object
has penetrated the OCS.
Alternatively, object penetration of the X Surface may be examined
by adjusting (or reducing) the height of the object by the amount
of rise to the object between the outer boundary of the W Surface
and the X Surface. If such adjustment is made, the adjusted object
height could be compared with the height of the W Surface, and if
the adjusted object height is greater than Z(w), then the object
has penetrated the OCS. An object height adjustment factor Q(x) of
the X Surface may be determined by using approach design criteria.
As shown by formula 4-11 in FIG. 4A, Q(x) may be determined as a
function of D(xp) and W(w).
Similarly, object penetration of the Y Surface may be examined by
adjusting (or reducing) the height of the object by the amount of
rise to the object between the outer boundary of the W Surface and
the X and Y Surfaces. If such adjustment is made, the adjusted
object height could be compared with the height of the W Surface,
and if the adjusted object height is greater than Z(w), then the
object has penetrated the OCS. An object height adjustment factor
Q(y) of the Y Surface may be determined by using approach design
criteria. As shown by formula 4-12 in FIG. 4A, Q(y) may be
determined as a function of W(x), W(w), and D(yp).
Object penetration of the OCS may be examined by determining an
effective object mean sea level elevation O(ee) of the object
elevation Z(obs). Then, O(ee) may be compared with Z(we), and if
O(ee) is greater than Z(we), then the object has penetrated the OCS
by a penetration distance p. In such evaluation, elevation
LTP(elev) and radius r could serve as a reference datum in approach
design criteria. As shown by formula 4-13 in FIG. 4B, O(ee) may be
determined as a function of Z(obs), r, LTP(elev), D(obs), and Q,
where D(obs) is the perpendicular distance between a point on the
course centerline and the object, and if applicable, Q is Q(x) or
Q(y).
An OCS that has been penetrated may be adjusted if necessary. The
adjustment may be necessary if an object is penetrating the OCS and
no remedy exists to address the penetration. In one embodiment, an
adjustment could be made through the use of an iterative process as
discussed in detail below. In an alternative embodiment, an
adjustment could be made through the use of a path construction
function as discussed in detail below.
In an alternative embodiment, the adjustment of the OCS could
depend on a minimum obstacle clearance distance between the
penetrating object and the glidepath at a corresponding location of
the penetrating object. The height or elevation of the glidepath
could be vertically offset by the value of a minimum obstacle
clearance distance. The value of a minimum obstacle clearance
distance could be fixed or variable determined as a function of one
or more criteria by a manufacturer or end user. For example, it may
be determined as a function of alerting criteria established for a
TAWS system. For each penetrating object, if the height or
elevation of the object does not exceed the height or elevation of
the vertically offset glidepath corresponding to the location of
the object, then the adjustment to the OCS may not be
necessary.
If an adjustment is made, it could be limited. For example, the
values of LTP(elev) and GPA may be limited by approach design
criteria, where such limitation could be based on the category of
aircraft.
One of the purposes of examining an OCS for object penetration is
to establish a decision altitude of the approach procedure. A
decision altitude may be an altitude along the final approach
descent path (or glidepath) at which a missed approach must be
initiated if, for instance, visual references of the runway
environment have not been acquired by the pilot or flight crew. The
value of a decision altitude may be affected if the OCS has been
penetrated and no means are available to adjust the OCS.
A decision altitude DA may be determined by using approach design
criteria. As shown by formula 4-14 in FIG. 4B, DA of an OCS free of
object penetration may be determined as a function of height above
threshold HATh and LTP(elev), where HATh is the height of the DA
above the LTP. As shown by formula 4-15 in FIG. 4B, a distance
D(DA) along the final approach course between the LTP and the
position on the W OCS corresponding to DA may be determined as a
function of LTP(elev), TCH, .theta., DA, and r.
Alternatively, values representative of height above touchdown HAT
and touchdown zone elevation TDZE may be substituted for HATh and
LTP(elev) in formula 4-13, respectively. Values of HATh and HAT may
be dependent upon the type of approach. For example, HATh or HAT
could be set to 200 feet for the type of approach categorized as a
precision approach.
If an OCS is not free of object penetration, adjustments may be
made to address the penetration if no remedy exists. The aviation
governing authority could determine whether the object can be
moved, removed, or adjusted downward, or whether the runway could
be displaced. Also, adjustments or revisions could be made to a
.theta., a DA, and a TCH.
The GPA 308 could be adjusted or revised using approach design
criteria. As shown by formula 4-16(a) in FIG. 4B, a revised
glidepath angle GPA(rev) may be determined as a function of
LTP(elev), d, O(ee), and D. Alternatively, as shown by formula
4-16(b) of FIG. 4B, GPA(rev) could be determined as a function of
D, d, S, and p, where p may be the distance of object penetration.
The value of GPA(rev) may be subject to a limitation, however,
based upon an approach category assigned to the aircraft, where
such category may be based upon an aircraft speed.
The DA could be adjusted or revised using approach design criteria.
It may be preferable to see the lowest DA possible so that the
aircraft can to get as close as possible to the runway. As shown by
formula 4-18 in FIG. 4B, an adjusted decision altitude DA(adj) may
be determined as a function of r, d, LTP(elev), TCH, 8, O(ee), and
D(adj), where D(adj) may be a distance along the final approach
course between the LTP and the position on the W OCS where the
elevation of the W OCS is equal to O(ee). The TCH could be adjusted
or revised using approach design criteria. As shown by formula 4-17
in FIG. 4B, a revised threshold crossing height TCH(rev) may be
determined as a function of 8, d, p, and Z(relief), where Z(relief)
may be the maximum W Surface relief that may be achieved by
adjusting TCH. The value of TCH(rev) may be limited to a range
between a minimum allowable TCH and a maximum allowable TCH. As
stated above, the determination of a decision altitude DA may
depend on whether an OCS has been penetrated or not. This includes
an OCS associated with a missed approach procedure. The drawings of
FIG. 5 illustrate an OCS that could be applicable to a missed
approach segment of a precision final approach or an LPV approach
(not drawn to scale). FIG. 5A presents a plan view and profile view
of an OCS having a slope and located below a climb path; the OCS is
depicted as a continuation of a final approach course as shown in
FIG. 5A.
As illustrated in the drawings of FIG. 5, the location of DA 350
could be the beginning of section 1a of a missed approach, and a
second location shown by item 352 could be the end of section 1a.
Section 1a may be a continuation of the final approach OCS for
distance L(a1) from DA 350 using approach design criteria. This
distance could be fixed or variable, and as shown in FIG. 5A, L(a1)
is fixed at 1,460 feet. The continuation of the final approach OCS
is advantageous because it accommodates for the height loss
associated with the transition from the final approach glidepath
354 to the missed approach. The W OCS, X OCS, and Y OCS of the
final approach OCS are identified in section 1a as 1aW OCS, 1aX
OCS, and 1aY OCS of the missed approach OCS. The approach design
criteria and formulas stated above regarding OCS dimensions, object
penetration examination, and adjustments or revisions to a GPA, a
DA, and a TCH to address an object penetration could still apply in
section 1a. For example, widths W(1aw), W(1ax), and W(1ay) of the W
OCS, X OCS, and Y OCS at the end of section 1a may be determined
using formulas 4-4, 4-5, and 4-6, respectively, where D=D(DA)-L(a1)
or D=D(adj)-L(a1), as applicable. For another example, the
elevation Z(a1) at the end of 1aW OCS may be determined using
formula 4-10, where D=D(DA)-L(a1) or D=D(adj)-L(a1), as
applicable.
As illustrated in the drawings of FIG. 5, section 1b may begin at a
location shown by item 352 and end at a location shown by item 356.
Section 1b may be comprised of a plurality of surfaces, and as
shown, it is comprised of a 1bW surface ("1bW OCS"), a 1bX surface
("1bX OCS"), and a 1by surface ("1by OCS"). The slope S(ma) 358 of
these surfaces is depicted as having a run over rise of 28.5:1, and
a climb gradient ("CG") 360 of the climb path is depicted as having
a run over rise of 200 feet/NM. As shown by formula 6-1 in FIG. 4A,
slope S(ma) may be measured as run over rise and may be determined
as a function of CG (as measured in units of feet/NM) using
approach design criteria.
Also, 1bX OCS and 1bY OCS may laterally slope. Like the X OCS and Y
OCS of the final approach OCS above, the 1bX OCS is a laterally
sloping surface having an outward run over rise of 4:1 from each
outer boundary of the 1bW OCS and 1by OCS is laterally sloping
surface having an outward run over rise of 7:1 from each outer
boundary of the 1bx OCS.
Each of the section 1b surfaces may begin from the end of its
respective section 1a surface and extend to a distance
ascertainable using approach design criteria. This length L(1b) of
the 1b surface could be fixed or variable, and as shown in FIG. 5,
it is fixed at 8,401 feet. The width of the 1b surface expands
outwardly from a missed approach course centerline, i.e., the
lateral boundaries of the OCS become wider. As shown in FIG. 5, the
outward expansion could be linear until reaching the end at line
ab. The width W(1b) at the end surface 1b is shown to be 3,308 feet
on either side of the missed approach course centerline.
The outer boundaries of the 1bW OCS, 1bX OCS, and 1bY OCS may be
determined using approach design criteria. For example,
perpendiculars extending from points along the missed approach
course centerline may be used to locate corresponding points along
each of the boundaries. As shown by formulas 6-2, 6-3, and 6-4 in
FIG. 6, perpendicular distances W(1bw), W(1bx), and W(1by) between
a point on the course centerline and respective points on the 1bW
OCS boundary, 1bX OCS boundary, and 1bY OCS boundary may be
determined as functions of distance D(1b), L(1b), W(1b), W(law),
W(1ax), and W(1ay) as applicable, where D(1b) may be the distance
between the course centerline end of section 1a and a point along
the centerline.
The elevations Z(1bw), Z(1bx), and Z(1by) of any point of the 1bW
OCS, 1bX OCS, and 1by OCS, respectively, may be determined using
approach design criteria. As shown by formulas 6-5, 6-6, and 6-7 in
FIG. 6A, elevations Z(1bw), Z(1bx), and Z(1by) may be determined as
functions of Z(a1), D(1b), r, S(1b), D(1bxp), and D(1byp), where
D(1bxp) is the perpendicular distance between the missed approach
course centerline and a point below the point on the 1bx OCS, and
D(1byp) is the perpendicular distance between the course centerline
and a point below the point on the 1bY OCS.
After an OCS has been created for section 1b, it may be examined
for surface object penetration. Object penetration of the 1bW
surface may be examined by comparing Z(1bW) with the object height,
and if the object height is greater than Z(1bw), then the object
has penetrated the OCS. Object penetration of the 1bX surface and
1bY surface may be examined by adjusting (or reducing) the height
of the object by the amount of rise to the object between the outer
boundary of the 1bW surface and the 1bX surface and 1bY surface. If
such adjustment is made, the adjusted object height could be
compared with the height of the 1bW surface, and if the adjusted
object height is greater than Z(1bw), then the object has
penetrated the OCS. An object height adjustment factor Q(1bx) of
the X surface and Q(1by) of the Y surface may be determined by
using approach design criteria. As shown by formulas 6-8 and 6-9 in
FIG. 6A, Q(1bx) and Q(1by) may be determined as functions of
D(1bxp), W(1bw), and W(1bx), W(1bw), and D(1byp) as applicable.
Object penetration of the section 1b OCS may be examined by
determining an effective object mean sea level elevation O(ee) of
the object elevation Z(obs). Then, O(ee) may be compared with
Z(1bw), and if O(ee) is greater than Z(1bw), then the object has
penetrated the OCS by a penetration distance p. By using formula
4-13 shown in FIG. 4B, O(ee) may be determined as a function of
Z(obs), r, LTP(elev), D(obs), and Q, where D(obs) is the
perpendicular distance between a point on the missed approach
course centerline and the object, and Q is Q(1bx) or Q(1by) (if
applicable).
As discussed above, penetration may be permissible if a minimum
obstacle clearance distance between the penetrating object and the
climb path at a corresponding location of the penetrating object.
Likewise, the height or elevation of the climb path could be
vertically offset by the value of a minimum obstacle clearance
distance. In one embodiment, the height or elevation of the climb
path could be vertically offset by the value of a minimum obstacle
clearance distance. For example, it may be determined as a function
of a required terrain clearance requirement applicable for a
departure or alerting criteria established for a TAWS system. For
each penetrating object, if the height or elevation of the object
does not exceed the height or elevation of the vertically offset
climb path corresponding to the location of the object, then the
adjustment to the OCS may not be necessary. In another embodiment,
an adjustment could be made through the use of an iterative process
as discussed in detail below. In an alternative embodiment, an
adjustment could be made through the use of a path construction
function as discussed in detail below.
If an adjustment is made, it could be limited. For example, the
values of LTP(elev) and GPA may be limited by approach design
criteria, where such limitation could be based on the category of
aircraft.
The existence of an obstacle penetrating a surface of the section
1b OCS may affect the determination of the decision altitude DA of
the final approach descent path (or glidepath) by raising it and
moving it further away from the LTP if an OCS may not be adjusted.
As shown by formula 6-10 in FIG. 6, an adjusted decision altitude
DA(1badj) may be determined as a function of LTP(elev), TCH,
.theta., D(DA), and D(1badj), where D(1badj) may be a distance
along the final approach course the DA point moves further away
from the LTP and based on the numerical values shown in FIG. 5.
The drawings of FIG. 7 illustrate an OCS comprised of a plurality
of surfaces that could be applicable to a final approach segment of
a LNAV/VNAV approach (not drawn to scale); the shaded portions
indicate the OCS. FIG. 7A presents a plan view and profile view of
an OCS having a slope 402 and located below a glidepath 404
extending from a FPCP 406 and having a GPA 408 of .theta.; as
stated above, an FPCP may be an imaginary point above the LTP 410
(or an FTP) at the TCH from which the glidepath mathematically
emanates. Slope S may be measured as run over rise. Slope could
also be based on a temperature spread, where the temperature spread
could be the difference between an airport International Standard
Atmosphere temperature ISA associated with an airport elevation and
an average coldest temperature ACT associated with the airport
(which could be a standard temperature for the location of the
airport or a temperature determined using historical temperature
records). As shown by formula 8-1 in FIG. 8, slope S may be
determined as a function of GPA 408, ISA, and ACT.
As stated above, the origination of an OCS may be determined using
a point of reference. As embodied in FIG. 7A, an LTP 410 of a
runway 412 (or FTP if applicable) could serve as a reference point
from which the origin or beginning of an OCS, i.e., the OCS origin
414, may be determined. As depicted in FIG. 7A, the OCS (shown as
shades) could begin at a distance D(o) 416 from the LTP 410
measured along the final approach course centerline 418. Distance
D(o) may be determined using approach design criteria. As shown by
formula 8-2 in FIG. 8B, D(o) may be determined as a function of TCH
and .theta..
The OCS could extend to a second position located at a fixed
distance from an OCS origin 414 or some other position determinable
through the application of approach design criteria. As depicted in
FIG. 7A, the OCS extends to a position determinable as a fixed
distance from a PFAF 420; specially, the OCS extends 0.3 miles
beyond the PFAF 420. The distance D(PFAF) between the LTP 410 and
PFAF 420 may be determined using elevation LTP(elev) and r as
reference data in approach design criteria. As shown by formula 8-3
in FIG. 8B, D(PFAF) may be determined as a function of the
LTP(elev), r, .theta., TCH, and alt(min).
As an OCS extends away from the runway 412, the width of the OCS
may remain constant until reaching a position determinable through
the application of approach design criteria, and then expands
outwardly from a final approach course centerline 418 so that the
lateral boundaries of the OCS become wider. The outward expansion
could be linear as shown in FIG. 7A. FIGS. 7B and 7C depict
cross-sections of an OCS at a first location located 1.0 NM before
a PFAF 420 and a second position located 0.3 NM beyond a PFAF 420,
respectively. A comparison between FIGS. 7B and 7C illustrates a
difference in widths not only of an OCS between the two locations
but also a difference in widths between the Primary OCS ("P OCS")
and Secondary OCS ("S OCS") beginning at a position located 1.0 NM
before the PFAF 420.
The outer boundaries of the primary OCS and secondary OCS between
positions located 1.0 NM before the PFAF 420 and 0.3 NM beyond the
PFAF 420 may be determined using approach design criteria. For
example, perpendiculars extending from points along the final
approach course centerline 418 may be used to locate corresponding
points along each of the boundaries. As shown by formulas 8-4 and
8-5 in FIG. 8, perpendicular distances W(p) and W(s) between a
point on the course centerline and respective points on the P OCS
and S OCS boundaries may be determined as a function of D(PFAF) and
distance D, where D is the distance between a LTP or FTP and a
point on the course centerline.
Application of formulas 8-4 and 8-5 result in the distances shown
in FIG. 7B. The outer boundaries of the P OCS and S OCS at the OCS
origin 414 are 3,645.6 feet and 5,468.4 feet (i.e.,
3,645.6'+1,822.8'), respectively, and perpendicular to the
centerline of the final approach course located at the midpoint of
the P OCS. Likewise, as shown by the distances shown in FIG. 7C,
the outer boundaries of the P OCS and S OCS at a position 0.3 NM
beyond the PFAF 420 are 7,331.7 feet and 10,997.55 feet (i.e.,
7,331.7'+3,665.85'), respectively, and perpendicular to the
centerline of the final approach course located at the midpoint of
the P OCS.
As stated above, an OCS may comprise of one or more laterally
sloping surfaces. As indicated in both FIGS. 7B and 7C, S OCS is a
laterally sloping surface having an outward run over rise of 7:1
from each outer boundary of the P OCS.
After an OCS has been created, it may be examined for object
penetration of the OCS. Approach design criteria may require the
application of the OCS to being at a point where the OCS reaches a
height specified in the criteria. Object clearance distance height
h(OCS) may be a height above the LTP(elev); for the OCS of FIG. 7A,
h(OCS) is assumed to be equal to 89 feet (not shown). With h(OCS),
the distance D(OCS) from the LTP to the position along the final
approach course centerline where the application of the OCS may
begin for the purpose of examining for penetration. As shown by
formula 8-6 in FIG. 8, D(OCS) may be determined as a function of
LTP(elev), S, D(o), r, and h(OCS).
The elevation Z(p) of the P OCS at any point along the final
approach course centerline at a distance D from the LTP may be
determined by using approach design criteria. As shown by formula
8-7 in FIG. 8, Z(p) may be determined as a function of LTP(elev),
D(OCS), S, D, and r.
Z(obs) may be compared with Z(p) of any point on the OCS to examine
for object penetration of the OCS. For an object located with the
boundaries of S OCS, the elevation of the object may be adjusted or
reduced by the amount of rise to the object between the outer
boundary of the P surface and the S surface. If such adjustment is
made, the adjusted object elevation Z(adj) may be compared with
Z(p) to examine for object penetration of the OCS. By using formula
8-8 (4-10) shown in FIG. 8, Z(adj) may be determined as a function
of Z(obs), D(sp), and W(p), where Z(sp) is the perpendicular
distance between the course centerline and a point below the point
on the S OCS. Then, if Z(obs) or Z(adj) is greater that Z(p), then
the object has penetrated the OCS.
As discussed above, an OCS that has been penetrated may be adjusted
if necessary. The adjustment may be necessary if an object is
penetrating the OCS and no remedy exists to address the
penetration. In one embodiment, an adjustment could be made through
the use of an iterative process as discussed in detail below. In an
alternative embodiment, an adjustment could be made through the use
of a path construction function as discussed in detail below.
In an alternative embodiment, the adjustment of the OCS could
depend on a minimum obstacle clearance distance between the
penetrating object and the glidepath at a corresponding location of
the penetrating object. The height or elevation of the glidepath
could be vertically offset by the value of a minimum obstacle
clearance distance. The value of a minimum obstacle clearance
distance could be fixed or variable determined as a function of one
or more criteria by a manufacturer or end user. For example, it may
be determined as a function of alerting criteria established for a
TAWS system. For each penetrating object, if the height or
elevation of the object does not exceed the height or elevation of
the vertically offset glidepath corresponding to the location of
the object, then the adjustment to the OCS may not be
necessary.
If an adjustment is made, it could be limited. For example, the
values of LTP(elev) and GPA may be limited by approach design
criteria, where such limitation could be based on the category of
aircraft.
One of the purposes of examining an OCS for object penetration is
to establish a decision altitude of the approach procedure. A
decision altitude DA may be determined by using approach design
criteria. As shown by formula 8-9A in FIG. 8, DA may be determined
as a function of h(OCS) or Z(obs) (Z(adj) if applicable). If one or
more objects penetrate the OCS, DA may be determined with other
approach design criteria. As shown by formula 8-9B in FIG. 8, DA
may be determined as a function of .theta., Z(obs) (or Z(adj) if
applicable), D(o), LTP(elev), S, TCH, and r, where Z(obs) or Z(adj)
is the elevation of the highest penetrating object. After
determining the higher DA, the distance D(DA) from the LTP may be
determined by approach design criteria. As shown by formula 8-10 in
FIG. 8, D(DA) may be determined as a function of LTP(elev), TCH,
.theta., and DA.
The final approach course centerline 418 of the final approach
course of the OCS depicted in FIG. 7 is shown as being aligned with
an extended runway centerline; however, as depicted in FIG. 2B, the
final approach course 230 may be offset 226 from an extended runway
centerline 232. If an offset is used, approach design criteria
could impose limits. For example, an LNAV/VNAV approach may be
limited to an angle .alpha. no greater than 15 degrees. Design
criteria may also impose a distance restriction for the
intersection of the final approach course centerline 418 and the
extended runway centerline. If a is less than or equal to 5
degrees, an approach may require the final approach course
centerline 418 to align the course through the LTP. If a is greater
than 5 degrees but less than or equal to 10 degrees, an approach
may require the final approach course centerline 418 to intersect
the extended runway centerline at a point located at a distance d1
between 1,500 and 5,200 feet prior to the LTP. If an offset is
greater than 10 degrees but less than or equal to 15 degrees, an
approach may require the final approach course centerline 418 to
intersect the extended runway centerline at a point located at a
distance d1 between 3,000 and 5,200 feet prior to the LTP. Design
criteria may also impose a minimum height HATh(min) to the value of
the height above threshold. As shown by formula 8-11 in FIG. 8,
HATh(min) may be determined as a function of d1, .alpha., .theta.,
LTP(elev), TCH, and V(KIAS), where V(KIAS) is the indicated
airspeed in knots that may be determined by the category of the
aircraft. If the difference between the DA and LTP(elev) is less
than the HATh(min), then the DA may be adjusted or increased until
the difference is zero.
The drawings of FIG. 9 illustrate an application of an OCS to a
missed approach segment of a LNAV/VNAV approach (not drawn to
scale). As illustrated in the drawings of FIG. 9, the location of
DA 370 could be the beginning of section 1 of a missed approach,
and a second location shown by item number 372 could be the end of
section 1 which could be a specified height above the airport
elevation (e.g., 400'). It may comprise of one or more surfaces. It
may comprise a flat surface 374 and a rising surface 376 if a climb
to the specified height above the airport elevation is
necessary.
The area from the location of the DA 370 to the end of the flat
surface 378 may be termed a "flat surface." The length FSL of the
flat surface 374 may be constructed using approach design criteria.
As shown by formula 10-1 in FIG. 10, FSL may be determined as a
function of V(KIAS) and DA. The end of the flat surface is
nominally indicated by item 378; if the DA is lower than 400 feet
above the elevation of the airport, a rising surface having a slope
S(mas) (e.g., 40:1) could be added as a surface extension. The
length s1 of the extension could be determined by approach design
criteria. As shown by formula 10-2 in FIG. 10, s1 may be determined
as a function of Z(ext) and CG, where Z(ext) is number of feet
needed to climb to 400 feet above the airport elevation.
The outer boundaries of the P1 OCS and S1 OCS may be determined
using approach design criteria. For example, perpendiculars
extending from points along the missed approach course centerline
may be used to locate corresponding points along each of the
boundaries. As shown by formulas 10-3 and 10-4 in FIG. 10,
perpendicular distances W(p1) and W(s1) between a point on the
course centerline and respective points on the P1 OCS boundary and
S1 OCS boundary may be determined as functions of distance D(DA1),
where D(DA1) may be the distance between the DA point and a point
along the centerline.
The elevation Z(mas) of the OCS below the DA 380 may be determined
by approach design criteria. As shown by formula 10-4 in FIG. 10,
Z(mas) may be determined as a function of DA and h1, where h1 may
be a constant that depends on the category of aircraft.
For object penetration of the flat surface 374, approach design
criteria may require an examination of Z(obs) and Z(mas), and if
Z(obs) is greater that Z(mas), then the object has penetrated the
OCS by p; if penetration exists, then the DA may be raised by the
amount p. For object penetration of the rising surface 376,
approach design criteria may require the determination of an
adjusted decision altitude DA(mas). As shown by formula 10-6 (4-17)
in FIG. 10, DA(adj) may be determined as a function of p, .theta.,
and S(mas).
As embodied herein, a missed approach procedure may be a standard
or optional segment of an approach procedure. A missed approach
procedure could include an initial heading or track and altitude to
climb to a navigation fix. As noted from the discussion above,
Sections 1 of the object clearance surfaces for the LPV and
LNAV/VNAV missed approach procedures do not end at a navigation
fix. A Section 1 OCS may provide a link connecting a point
associated with a final missed approach with a point of a Section 2
OCS. For each OCS, Section 1 may terminate at a position
ascertainable by approach design criteria.
An OCS for Section 2 of a missed approach procedure may be
constructed using approach design criteria. Missed approach design
criteria may be established to allow a pilot to fly an aircraft
from the runway environment to a navigation fix. These criteria may
cover one or more types of missed approach procedures including,
but not limited to, straight approach procedures and turning
approach procedures. Although there could be more than one type of
missed approach procedure, each could require an OCS comprising of
one or more surfaces used in the evaluation of object clearance,
where each OCS may be defined using approach design criteria. Just
as approach design criteria was employed for constructing an OCS
and conducting an examination for object penetration in the
discussions above related to the exemplary LPV and LNAV/VNAV
procedures, approach design criteria may be employed for
constructing a Section 2 OCS between a point at the end of Section
1 to a navigation fix termination of the approach procedure. If an
object is found to penetrate a surface of a Section 2 OCS,
adjustments or revisions may be made if a remedy does not exist to
address the issue of object penetration.
In one embodiment, an adjustment could be made through the use of
an iterative process as discussed in detail below. In an
alternative embodiment, an adjustment could be made through the use
of a path construction function as discussed in detail below. In an
alternative embodiment, the adjustment of the OCS could depend on a
minimum obstacle clearance distance between the penetrating object
and the glidepath at a corresponding location of the penetrating
object. The height or elevation of the glidepath could be
vertically offset by the value of a minimum obstacle clearance
distance. The value of a minimum obstacle clearance distance could
be fixed or variable determined as a function of one or more
criteria by a manufacturer or end user. For example, it may be
determined as a function of alerting criteria established for a
TAWS system. For each penetrating object, if the height or
elevation of the object does not exceed the height or elevation of
the vertically offset glidepath corresponding to the location of
the object, then the adjustment to the OCS may not be
necessary.
If an adjustment is made, it could be limited. For example, the
values of LTP(elev) and GPA may be limited by approach design
criteria, where such limitation could be based on the category of
aircraft.
If no remedy exists, then adjustments or revisions may be made to a
final approach OCS, Section 1 OCS, and/or Section 2 OCS to ensure
object clearance for the entire approach procedure using approach
design criteria such as, for example, those adjustments or
revisions discussed above.
As stated above, approach design criteria may be developed by an
aviation-governing authority. For the purposes of illustration and
not limitation, FAA Orders 8260.3B and 8260.54A contain approach
design criteria for generating an OCS associated not only for final
approach and Section 1 missed approach procedures but also for a
Section 2 missed approach. Not only do the Orders contain criteria
associated with LPV and LNAV/VNAV approach procedures, but they
contain criteria for generating other approach procedures not
discussed herein. As stated above, the embodiments disclosed herein
could include any approach procedure using approach design criteria
to generate an OCS for the purpose of providing object clearance
between two or more ascertainable fixes or positions, where the
approach design criteria are not limited to those approach
procedures designed by the FAA. In the event changes are made to
existing approach design criteria or new approach design criteria
are developed, those skilled in the art will appreciate the ability
and ease with which executable software code may be reprogrammed or
modified by a manufacturer or end user to facilitate future changes
related to approach design criteria.
The advantages and benefits of the embodiments discussed herein may
be illustrated by showing examples of how approach data may be
generated for runways that have existing approach procedures but
may not provide vertical guidance or for runways that do not have
existing approach procedures (including those which may be limited
to specific category of aircraft). The generation of approach data
could also be made real-time during flight. As discussed above,
providing object clearance may be accomplished by ensuring an OCS
is free from object penetration. If adjustments or revisions are
made because of a penetrating object, this could result in an
undesirable increase to a DA. As embodied herein, object
penetration may be permitted which, in effect, permits a lower
DA.
FIGS. 11 and 12 depict two approach procedures established by the
FAA and modified for the purpose of discussion only. As presented
herein, they are not suitable for navigation. These are presented
herein for the purposes of discussion only. FIG. 11 illustrates
approach procedure "GPS RWY 26" established for Runway 26 at
Rifle/Garfield County Regional Airport ("RIL") in the State of
Colorado, United States, and FIG. 12 illustrates approach procedure
"LOC/DME-A." GPS RWY 26 of FIG. 11 is an approach procedure that
complies with RNAV approach design criteria. The lack of the words
"RNAV (GPS)" in the title "GPS RWY 26" may indicate that this
approach may have been an overlay of a previous approach that was
based on conventional, ground-based NAVAID but has since converted
to a stand-alone approach procedure using waypoints having located
at a specified latitude and longitude. Because this procedure could
have been predicated upon approach design criteria of a
ground-based NAVAID, it may not adhere to RNAV approach design
criteria for stand-alone GPS procedures such as, but not limited
to, LPV and LNAV/VNAV approach procedures.
As indicated in FIG. 11, approach design criteria applied for a
ground-based NAVAID approach (from which the GPS approach procedure
has been converted) may have produced a final approach course of
257.degree., a GPA of 3.68.degree., a Final Approach Fix ("FAF")
designated by the waypoint "ANTEJ" and having an altitude of at
least 9,500 feet, minimum decision altitude ("MDA") of 7,820' MSL,
and a MAP at the waypoint "SEQRY." Because this approach procedure
has been adopted for the use of aircraft installed with a GPS
navigation system including an airborne database, waypoints could
be stored in the database. The location of ANTEJ is latitude
("lat.") 39.degree.31'48.97'' N, longitude ("long.")
107.degree.29'57.22'' W, and the location of SEQRY is lat.
39.degree.31'33.85'' N, long. 107.degree.42'13.63'' W.
The LTP(elev) of Runway 26 has been surveyed to be 5,544' MSL (not
shown). By subtracting this value from the MDA, it is determined
that the minimum descent height ("MDH") of GPS RWY 26 is 2,276' AGL
(as referenced from the LTP). Those skilled in the art recognize
that the MDH is high. Other conventional, ground-based NAVAID
approach procedures published for Runway 26 have lower minimum
altitudes. An "ILS RWY 26" approach procedure has a DA of 7,100
feet (Decision Height ("DH") of 1,556' AGL), and a "LOC/DME-A"
approach procedure has an MDA of 7,400' MSL (MDH of 1,876' AGL);
the LOC/DME-A approach procedure will be discussed below; those
skilled in the art recognize that a DH and MDA (or DH and MDH)
serve the same function, where a DH is typically used in precision
approaches and MDH is typically used for non-precision approaches.
A comparison between the conventional, ground-based procedures and
the GPS-based procedure shows that the former procedures provide a
720' and 400' advantage over the latter.
At the time of this writing, RIL does not have a published RNAV
approach procedure that adheres to RNAV approach design criteria
for stand-alone approach procedures such as, but not limited to,
LPV and LNAV/VNAV approach procedures. The advantages and benefits
of the embodiments herein may be recognized through the
construction of approach procedures that could result in lower
minimum altitudes while drawing on existing waypoints and other
navigation fixes.
The existing waypoints of GPS RWY 26 could be used to possibly
construct a procedure using LNAV/VNAV approach design criteria. As
discussed above, the LNAV/VNAV procedure may be based on a
temperature spread between an airport ISA and the temperature to
which the approach procedure is protected and may be limited if the
reported temperature is below the ACT. For the purposes of the
remaining discussion herein, it will be assumed that there is no
temperature restriction.
As discussed above, the value of a GPA may be limited, and such
limitation could be based on the category of aircraft. For example,
a maximum allowable GPA for categories A, B, C, and D & E
aircraft may be 5.7.degree., 4.2.degree., 3.6.degree., and
3.1.degree., respectively, where such categories may be based upon
an aircraft speed. It is noted that the glidepath is 3.68.degree..
Because the maximum allowable GPA exceeds the glidepath for
categories C and D & E aircraft, this approach would be
unavailable for these categories of aircraft. As discussed below in
detail, a path finding function may be performed to determine a new
approach path, and from there, to construct an OCS from which
object penetration may be examined.
Assuming that the approach will be limited to category A and B
aircraft only, an OCS may be constructed using approach design
criteria as discussed above. For runway 26, the magnetic bearing is
260.6.degree., the LTP is located at lat. 39.degree.31'36.45'' N,
long. 107.degree.42'52.39'' W, and the TCH has been set to 59'.
Also, an object with an elevation of 5,969' is located
approximately 2.0 NM from the LTP. Application of approach design
criteria and associated functions of an LNAV/VNAV approach
procedure may yield a resulting DA of 5,814' MSL (DA of 270' AGL).
A comparison of the resulting DA and the MDA of the GPS RWY 26
procedure shows a decrease in the altitude of 2,006', which would
be recognized by those skilled in the art as a substantial
improvement because it permits the aircraft to descend further
along the glidepath to a lower altitude, allowing the pilot to fly
closer to the runway before he or she decides whether to land or
begin a missed approach procedure based, in part, on having the
runway environment in sight.
The existing waypoints of GPS RWY 26 approach procedure could be
used to possibly construct a procedure using LPV approach design
criteria. The final approach course is 257.degree.. As discussed
above, the LPV approach is limited to an offset of 3.degree.. A
comparison of the final approach course of 257.degree. and runway
bearing 260.6.degree. yields a result that exceeds the 3.degree.
limitation; as such, an LPV would not be available using the
established waypoints of GPS RWY 26 approach procedure.
Although LPV approach design criteria may not be applied to the
existing waypoints of GPS RWY 26, the existing waypoints of the
LOC/DME-A approach procedure shown in FIG. 12 could be used to
possibly construct a procedure using LPV approach design criteria;
the title of the approach procedure suggests that a conventional,
ground-based NAVAID comprising a localizer and a collocated
distance measuring equipment ("DME") are used to define the
procedure. A previous application of approach design criteria for a
localizer approach procedure may have produced a final approach
course of 261.degree., a GPA of 3.00.degree. (the standard GPA), an
FAF designated by the navigation fix "LOCAT" and having an altitude
of at least 9,800 feet, an MDA of 7,400' MSL, and a MAP at a
navigation fix located 2.7 NM from a localizer designated "I-RIL."
Although this approach procedure has not been adopted for the use
of aircraft installed with a GPS navigation system including an
airborne database, the FAA has determined that LOCAT is located at
lat. 39.degree.31'08.53'' N, long. 107.degree.32'29.30'' W, and
that MAP is located at lat. 39.degree.31'28.68'' N, long.
107.degree.41'04.04'' W. These coordinates may be stored in the
database and used as waypoints in the construction of a LPV
approach.
Application of approach design criteria and associated functions of
an LPV approach procedure may yield a resulting DA of approximately
6,300' MSL (DA of 756' AGL). A comparison of the resulting DA and
the MDA of the GPS RWY 26 procedure shows a decrease in the
altitude of 1,520' AGL, which would be recognized by those skilled
in the art as a substantial improvement. Although the construction
of an LPV procedure results in a DA of 6,300' MSL, the construction
of an LNAV/VNAV procedure results in a more preferable DA of 5,814'
MSL. As such, the construction of an LNAV/VNAV approach procedure
using the existing waypoints of GPW RWY 26 improves the chances of
a successful landing by an aircraft because it may descend closer
to the runway while ensuring an object-free glidepath based on an
OCS free from object penetration inherent in approach design
criteria.
It should be noted that the higher DA resulting from the
application of LPV approach design criteria has been due to the
object having the elevation of 5,969'. Had the OCS been free of
this object and assuming a GPA of 3.68.degree., then a DA of 5,744'
would have been yielded by the criteria and formulas, a 70'
improvement over the DA of the LNAV/VNAV approach procedure.
The preceding examples illustrate the use of existing waypoints
from published approach procedures, but other waypoints including
those associated with the airport and other approach published
procedures at the airport could be examined for possible use in the
construction of an approach procedure through the application of
approach design criteria and formulas. As stated above, the
embodiments herein are not limited to the criteria and formulas of
LPV and LNAV/VNAV approach procedures.
As stated above, an approach procedure could comprise both a final
approach procedure and a missed approach procedure. Also, an
examination conducted for object penetration of an OCS associated
with a missed approach could affect the final approach procedure
by, for example, increasing the computed DA. As such, it may be
necessary to reconstruct an OCS associated with a final approach
procedure in the event an OCS associated with a missed approach
procedure has been penetrated.
As noted above, the published MDA of the GPS RWY 26 approach
procedure is more than 2,000' above the DA determined using
LNAV/VNAV approach design criteria to the existing waypoints of GPS
RWY 26. If the missed approach OCS of the GPS RWY 26 approach
procedure was determined as a function of the MDA and distance to
the MDA from the runway threshold, then the OCS associated with the
missed approach procedure may be higher than the DH of the
constructed LNAV/VNAV approach procedure. An aircraft executing a
missed approach from the DH would begin below the OCS of the
existing OCS of GPS RWY 26. If the LNAV/VNAV approach procedure
incorporates the missed approach instruction of GPS RWY 26, then an
object-free missed approach path assured for the higher OCS cannot
assure an object-free missed approach path of a lower OCS inherent
with the lower DH. As such, an OCS would have to be generated for
the missed approach procedure.
Similar to the construction of the final approach procedures above,
existing waypoints or navigation points could be used to provide a
missed approach course for the possible construction of a procedure
using LNAV/VNAV missed approach design criteria. As indicated in
FIG. 11, the missed approach procedure comprises of waypoints
"SEQRY," "SAWOM," and "AWRAW," where AWRAW serves as a terminating
point of the missed approach procedure. This approach procedure has
been adopted for the use of aircraft installed with a GPS
navigation system including an airborne database, and such database
may be used to store waypoint location information. The location of
SAWOM is lat. 39.degree.29'23.81'' N, long. 107.degree.58'07.22''
W, and the location of AWRAW is lat. 39.degree.34'25.26'' N, long.
108.degree.21'13.58'' W.
Having established a missed approach course using existing
waypoints, an OCS may be constructed using missed approach design
criteria and functions for an LNAV/VNAV approach procedure;
unfortunately, if a standard climb gradient (e.g., 200 feet/NM) is
assumed, the missed approach OCS would suffer significant object
penetration as a result of the lower DH due to high terrain to the
west and south of RIL (not shown).
To address the object penetration, one or more alternatives may be
examined. In one alternative, an examination could be made to
determine that value of DA that, when applied to approach design
criteria and formulas, could result with the missed approach OCS
free from object penetration. Assuming a climb gradient of 200
feet/NM, the application of formulas would result in a DA having an
elevation of approximately 7,290', which is still an improvement of
the GPW RWY 26 and LOC/DME-A MDAs of 7,820' and 7,400',
respectively.
In another alternative, missed approach design criteria could be
revised or altered to include a real-time CG value based on the
actual flight conditions and not a standard, fixed value. As
discussed above, data representative of input factors 150 may be
acquired by or through aircraft systems and sensors and may be
provided to a processor 170 as input. When received, the processor
170 may process the data in accordance with a climb performance
algorithm that could contain the equation or equations defining
climb performance. As a result, the processor 170 may determine a
CG based upon the application of the real-time dynamic or static
input factors 150.
If the computed CG is higher than an assumed value used for the CG
(e.g., 200 feet/NM), the OCS would be elevated. Moreover, the use
of a real-time computation of CG could make it possible for the
LNAV/VNAV and GPS RWY 26 missed approach procedures to join up with
each other if the computed climb performance was sufficiently high
and the elevated OCS remained free of object penetration.
In another alternative, an examination could be made to determine
the availability of a departure procedure that has been adopted for
the runway such as, but not limited to, an Obstacle Departure
Procedure ("ODP") and Standard Instrument Departure ("SID"). Legs
or segments of the procedure defined by existing waypoints could
substitute for those of the LNAV/VNAV missed approach procedure
defined by the existing waypoints of the GPS RWY 26 approach
procedure. It should be noted that, although the discussion herein
may be drawn to ODPs or SID(s) published by the FAA, the
embodiments herein are not limited to SIDs but include and apply to
any procedure designed using, in whole or in part, criteria adopted
to ensure object clearance protection along a flight path(s)
described in the procedure.
FIG. 13 illustrates a published ODP for RIL designated as "SQUAT
TWO DEPARTURE (RNAV) (OBSTACLE)" ("SQUAT 2"). As indicated in FIG.
13, the obstacle departure procedure comprises of waypoints
"OMJIY," "YIRDU," and "SQUAT." This departure procedure has been
adopted for the use of aircraft installed with a GPS navigation
system including an airborne database, and such database may be
used to store waypoint location information. The location of OMJIY
is lat. 39.degree.31'45.11'' N, long. 107.degree.48'08.52'' W,
YIRDU is lat. 39.degree.26'58.58'' N, long. 108.degree.00'53.22''
W., and SQUAT is lat. 39.degree.18'33.90'' N, long.
108.degree.13'23.05'' W.
The presence of SQUAT 2 suggests that the path specified in the
departure procedure is clear from objects when a climb gradient of
397 feet/NM is sustained until the aircraft reaches 9,700' MSL;
thereafter, the standard climb gradient of 200 feet/NM would apply
until the aircraft reaches 10,500' along the track to SQUAT. Then,
after reaching SQUAT, an OCS may be constructed between SQUAT and
AWRAW to connect up with the terminating point of the GPS RWY 26
approach procedure, where an application of LNAV/VNAV missed
approach design criteria would result with an OCS free from
penetrating objects.
Moreover, missed approach design criteria could be revised or
altered so that estimated climb performance of the aircraft may be
used as the climb gradient criterion. If the estimated climb
performance is higher than the value previously used for the climb
gradient (e.g., 200 feet/NM), the OCS could be elevated. As such,
it could be possible to fly to AWRAW without having to fly to SQUAT
(the terminating point of the ODP). Instead, an OCS could be
constructed between OMJIY or YIRDU and AWRAW to connect up with the
terminating point of GPS RWY 26, where the revised or altered
missed approach design criteria could be applied to examine whether
either OCS is free from object penetration. If there is no
penetration, then the missed approach procedure could discontinue
using the ODP at OMJIY or YIRDU (as applicable) and fly directly to
AWRAW.
In another alternative, an examination could be made to determine
the availability of an existing waypoint or navigation fix used as
a terminating point of another missed approach procedure. That is,
borrowing a waypoint or navigation fix from another approach
procedure for use as a terminating point. For example, the
terminating point of the missed approach procedure for LOC-DME-A
comprises a conventional NAVAID known to those skilled in the art
as a VOR/DME ground-based station and identified as "RIL"
("RIL-VOR"). Although this approach procedure has not been adopted
for the use of aircraft installed with a GPS navigation system
including an airborne database, the FAA has determined that RIL-VOR
is located at lat. 39.degree.31'41.61'' N, long.
107.degree.42'58.61'' W. These coordinates may be stored in the
database and used as waypoints in the construction of a LNAV/VNAV
missed approach procedure. While the coordinates of RIL-VOR may be
known, those of the navigation fix identified in the missed
approach procedure as 4.0 NM DME on R-259 of the RIL-VOR may not.
The coordinates, however, may be computed using navigation data
representative the navigation: location distance (4.0 NM) and
direction information(259.degree.) from RIL-VOR.
Having established a missed approach course using existing
waypoints, an OCS may be constructed using missed approach design
criteria and functions for a LNAV/VNAV approach procedure; if a
climb gradient of 200 feet/NM is assumed, the missed approach OCS
would not suffer from object penetration as a result of the lower
DH at SEQRY.
As discussed above, a LNAV/VNAV approach procedure constructed
using the existing waypoints of GPS RWY 26 was not available to
Category C, D, and E aircraft because the GPA of 3.68.degree.
exceeded the limits set for these categories. If GPS RWY 26 had
been the only established approach procedure to runway 26, it may
be deduced that there is no established approach procedure for the
affected categories of aircraft. To address a situation where no
approach has been established for a runway, one or more
alternatives may be available for constructing a glidepath.
In one alternative, an iterative process may be established where
the maximum GPA for the category of aircraft may be used initially
for constructing a glidepath mathematically emanating from an FPCP,
where the FPCP may be determined as a function of the location of
LTP (or FTP) and TCH. Using approach design criteria, an OCS could
be constructed, the OCS could be examined for object penetration,
and a DA could be determined based on the examination. Then,
through an iterative process that varies GPA between a range of
limits, TCH between a range of limits, the location of LTP or FTP
between a range of maximum offsets, and the resulting GPI, a DA
could be determined with each successive iteration, where the
resulting GPI could be examined for intersection within the runway
touchdown zone. After the iteration has been completed, a DA may be
selected, and the GPA, LTP, and TCH corresponding to the selected
DA may be used to form a glidepath mathematically emanating from an
FPCP. A similar iterative process may be used with LPV approach
design criteria where such process could include acceptable values
of HATh as part of the iteration. Once selected, the DA could be
then be subjected to missed approach design criteria.
In another alternative, an approach path may be constructed by
using a path construction function. One such function is disclosed
in a published article written by Dr. Ryan S. Y. Young and Kristen
M. Jerome, "Long-Range, In-Flight 3D Trajectory Re-Planning with
Airborne E*" ION NTM 2008, 28-30 Jan. 2008, San Diego, Calif.
("Airborne E*"). This published article incorporated by reference
in its entirety. Although disclosed herein, the embodiments herein
are not limited to the Airborne E* path construction function but
include any function capable of generating a path free from objects
that may be developed from navigation data associated with an
airport and/or runway environment as discussed above. As embodied
herein, a curved approach path may be defined and comprise a final
approach path, a missed approach path, and/or departure path.
For the purpose of illustration and not limitation, Airborne E* may
be employed to define an approach path, where the approach path may
be the mission of Airborne E*. To define a final approach path, the
path construction function could be bounded between the airspace
surrounding the LTP and a second point such as, but not limited to,
the approximate location of a PFAF; alternatively, the second point
could be any existing or published waypoint near or in the vicinity
of an extended runway centerline extending beyond the PFAF. To
define a missed approach path, the path construction function could
be bounded between the airspace surrounding the decision altitude
point and a second point such as, but not limited to, a terminating
point of an existing or published missed approach; alternatively,
the second point could be any existing or published waypoint near
or in the vicinity of an airport.
Once an approach path has been defined, an OCS can be constructed
and examined for object penetration using approach design criteria
and adjusted if penetrated and no remedy exists to allow the use of
a penetrated OCS. Then, applicable decision altitude data could be
determined and used in the generation of approach procedure
data.
As embodied herein, a path construction function may be used as a
remedy to determine whether an alternative path could be
constructed meeting approach design criteria. For example, a path
construction function may be applied after any adjustment or
revision is made to .theta., a DA, and a TCH. If an adjustment is
made, it could be limited. For example, the values of LTP(elev) and
GPA may be limited by approach design criteria, where such
limitation could be based on the category of aircraft.
FIG. 14 depicts a flowchart 600 of an example of a method for
generating procedure data used in an avionics system. The flowchart
begins with module 602 with the receiving of navigation data and
object data or data representative of navigation information and
object information by a processor 170. As discussed above,
navigation database 140 could contain information associated with,
but not limited to, ground-based navigational aids, waypoints,
holding patterns, airways, airports, heliports, instrument
departure procedures, instrument arrival procedures, instrument
approach procedures, runways, precision approach aids, company
routes, airport communications, localizer and airway markers,
restrictive airspace, airport sector altitudes, enroute airways
restrictions, enroute communications, preferred routes, controlled
airspace, geographical references, arrival and/or departure flight
planning, path point records, and GNSS Landing Systems. As embodied
herein, the receiving of data by a processor or the providing of
data to a processor may include a step in which the processor
performs a retrieval operation of such data.
Object data may be received from an object data source may include,
but is not limited to, a terrain database 132, an obstacle database
134, other aircraft systems 136, or any combination thereof. As
embodied herein, object data could include terrain information,
obstacle information, or both. A terrain database 132 may be
associated with a TAWS. As discussed above, an SVS system could
provide a source of object data. In addition to database sources of
object data, a non-database terrain and/or obstacle acquisition
system could provide a source of object information. Such system
may include, but is not limited to, a radar-based TAWS system.
The flowchart continues with module 604 with the defining of a
flight path for a final approach path. The path for a final
approach procedure could be a glidepath. A glidepath may have a
constant GPA. An approach path may comprise of one or more
ascertainable points. One point of a glidepath may be an FPCP, and
another point could be a PFAF. One or more points could correspond
to existing waypoints contained in a published approach procedure,
where the waypoints may establish a specific location (e.g.,
longitude/latitude coordinate) and could be used to describe a
variety of fixes in a final approach procedure including, but not
limited to, RNAV waypoints, ground-based NAVAIDs, navigation fixes
defined using ground-based NAVAIDs, and point(s) on a runway.
In one embodiment, data representative of an existing or published
approach procedure may be used to establish a final approach path
as embodied herein. For instance, a GPA of an existing approach
procedure may be used. In an embodiment disclosed herein, a
glidepath associated with a final approach could be defined by two
or more fixes of a published or established approach procedure. For
example, the location of a first fix could be a landing threshold
point of a runway, and the location of a second fix could be a
final approach fix. The height of the first fix could be defined as
the value of a threshold crossing height, and the height of the
second fix could be determined as a function of approach design
criteria.
If an existing or published approach procedure has not been
established for the runway or is unavailable for use because of,
for example, a restriction based on a category of the aircraft,
alternative means may be employed to establish a glidepath. In one
embodiment, a glidepath may be derived through an iterative process
such as, but not limited to, the process discussed above. In
another embodiment, a glidepath may be derived through a path
construction function. As discussed above, the employment of a path
construction function could produce a curved final approach path.
If a path construction function is employed, the design criteria
functions applicable to a straight path could still be applied to a
curved path. For example, the distance along the final approach
course could be applied as the distance along the curved path is
used, from where width of an OCS may be determined for the purpose
of examining for object penetration. Moreover, restrictions or
limitations including, but not limited to, those based on an offset
of a final approach course and/or categories of aircraft could
apply to a curved path.
The flowchart continues with module 606 with the construction of an
OCS for a final approach path. As discussed herein, the final
approach OCS may be constructed using design criteria. Design
criteria could include data representative of the glidepath such
as, but not limited to, GPA and runway magnetic bearing. Also,
final approach design criteria could include navigation data
representative of the runway and final approach procedure
information such as, but not limited to, LTP, LTP(elev), TCH, ACT,
and alt(min).
The flowchart continues with module 608 with the examining of the
approach OCS for object penetration. Design criteria may be applied
to determine whether object penetration has occurred, that is,
whether the vertical measurement of at least one object exceeds the
vertical measurement of the OCS at the location of the object. If
the height or elevation of at least one object exceeds the height
or elevation of the OCS at the location of the object, object
penetration has occurred.
The flowchart continues with module 610 with the adjusting of the
OCS using approach design criteria if necessary. The adjustment may
be necessary if an object is penetrating the OCS and no remedy
exists to address the penetration or to allow the use of a
penetrated OCS. In one embodiment, an adjustment could be made
through the use of an iterative process. In an alternative
embodiment, an adjustment could be made through the use of a path
construction function.
In an alternative embodiment, the adjustment of the OCS could
depend on a minimum obstacle clearance distance between the
penetrating object and the glidepath at a corresponding location of
the penetrating object. The height or elevation of the glidepath
could be vertically offset by the value of a minimum obstacle
clearance distance. The value of a minimum obstacle clearance
distance could be fixed or variable determined as a function of one
or more criteria by a manufacturer or end user. For example, it may
be determined as a function of alerting criteria established for a
TAWS system. For each penetrating object, if the height or
elevation of the object does not exceed the height or elevation of
the vertically offset glidepath corresponding to the location of
the object, then the adjustment to the OCS may not be
necessary.
If an adjustment is made, it could be limited. For example, the
values of LTP(elev) and GPA may be limited by approach design
criteria, where such limitation could be based on the category of
aircraft.
The flowchart continues with module 612 with the determining of
applicable decision altitude data, where such data could include
the decision altitude and distance to the decision altitude point
using approach design criteria. Applicability of the decision
altitude data may depend on whether the OCS was adjusted. If the
OCS was adjusted, then the adjusted applicable decision altitude
may be used as the applicable decision altitude data.
The flowchart continues with module 614 with the generation of data
representative of a final approach procedure. A final approach
procedure could include a glidepath passing through at least two
fixes, where each fix may be defined by a waypoint with a
corresponding altitude. A glidepath could pass through a final
approach fix and a decision altitude fix. The altitude of these
fixes could be determined using approach design criteria. In one
embodiment, the waypoint of the PFAF could be the same waypoint of
an existing FAF of an established final approach procedure; in
another embodiment, the PFAF waypoint could be determined using
approach design criteria. The decision altitude could be determined
using approach design criteria. In another embodiment, a third fix
through which a glidepath could pass through is a missed approach
point. A waypoint that could define this point may be the LTP with
a corresponding altitude comprising the sum of LTP(elev) and TCH
and (or TCH(adj) if applicable).
As embodied herein, a final approach procedure could be constructed
with a plurality of data. In one example, data representative of
distance information between two fixes could be incorporated into
the final approach procedure by computing the distances between the
two. In another example, data representative of the vertical angle
information of the glidepath (which could be the negative value of
the GPA) could be incorporated into the final approach procedure;
if such incorporation is made, it could be made to a GPA with a
value other than a standard value. In another example, data
representative of distance information between two fixes could be
incorporated into the final approach procedure by computing the
distances between the two. In another example, data representative
of path geometry could be incorporated into the final approach
procedure including, but not limited to, defining the leg types
between the fix or fixes as a track to a fix ("TF") which a known
descriptor field commonly employed by an FMS. In another example,
data representative of altitude description information could be
incorporated into the final approach procedure to describe a
waypoint crossing characteristic appropriate for the waypoint.
The flowchart continues with module 616 with the providing of data
representative of the final approach procedure to at least one
avionics system. In one embodiment, the system could be an FMS. In
another embodiment, the system could be display units. Display
units may include, but are not limited to, a tactical display unit,
a strategic display unit, a HUD unit, or a display unit which may
display approach path information. As embodied herein, final
approach procedure data could be used, in part or in whole, in the
generation of a flight route corridor image. In another embodiment,
the avionics system could be a vision system which generates an
image data set which represents the image displayed on a display
unit. Vision systems include, but are not limited to, SVS, EVS,
combined SVS-EVS, or combination thereof. As embodied herein, final
approach procedure data could be included, in part or in whole, in
the generation of an image data set. As embodied herein, the image
represented the image data set could include an image of a flight
route corridor. Then, the flowchart ends.
It should be noted that, although missed approach data may be
included as part of a published approach procedure, there could be
an occasion where only a final approach procedure is needed or may
be useful without the inclusion of a missed approach procedure. For
example, student and/or flight crew training may want to emphasize
flying a final approach procedure up through a missed approach
point or decision altitude point, at which time a choice could be
made to practice a final approach procedure, thereby bypassing the
practice of flying a missed approach procedure and the added
expense (e.g., fuel expense).
FIG. 15 depicts a flowchart 700 of an example of a second method
for generating procedure data used in an avionics system. The
flowchart begins with module 702 with the defining of a missed
approach path. A missed approach path may include a transition
between the glidepath and a climb path, where the glidepath may be
represented in the final approach procedure data generated in
module 614. A climb path may have a constant climb gradient. A
missed approach path may comprise of one or more ascertainable
points. One of the ascertainable points through which the missed
approach path could pass may be the decision altitude point
determined in module 612. One or more points could be points
determined by approach design criteria. One or more points could be
existing waypoints and altitudes. One or more points could
correspond to existing waypoints contained in an existing or
published approach procedure, where the waypoints could be used to
describe fixes of an approach procedure including, but not limited
to, RNAV waypoints, ground-based NAVAIDs, navigation fixes defined
using ground-based NAVAIDs, and point(s) on a runway.
In one embodiment, data representative of an existing or published
approach procedure may be used to establish a missed approach path
as embodied herein. For instance, a climb gradient of an existing
approach procedure may be used. In an embodiment disclosed herein,
a climb path associated with a missed approach could be defined by
two or more fixes of a published or established approach procedure.
For example, the location of a first fix could be a decision
altitude point, and the location of a second fix could be a holding
fix or some other fix signifying the terminating end of the missed
approach fix. The height of the first fix could be defined as the
value of a decision altitude, and the height of the second fix
could correspond to the altitude assigned in the published or
existing approach procedure.
If an existing or published approach procedure has not been
established for the runway or is unavailable for use because of,
for example, a restriction based on a category of the aircraft,
alternative means may be employed to establish a missed approach
path. In one embodiment, an existing or published ODP or SID could
be used as a missed approach path as discussed herein. In another
embodiment, a missed approach path may be derived through an
iterative process such as, but not limited to, the process
discussed above. In another embodiment, a missed approach path may
be derived through a path construction function. As discussed
above, the employment of a path construction function could produce
a curved missed approach path. If a path construction function is
employed, the design criteria functions applicable to a straight
path could still be applied to a curved path. For example, the
distance along the missed approach course could be applied as the
distance along the curved path is used, from where width of an OCS
may be determined for the purpose of examining for object
penetration. Moreover, restrictions or limitations could apply to a
curved path.
The flowchart continues with module 704 with the construction of a
missed approach OCS. As discussed herein, the missed approach OCS
may be constructed using missed approach design criteria. Data
representative of the final approach OCS constructed in module 606
and, if it was necessary, adjusted in module 610 could be used in
the missed approach design criteria. Also, final approach procedure
data generated in module 614 may be used by missed approach design
criteria.
The flowchart continues with module 706 with the examining of the
missed approach OCS for object penetration. Missed approach design
criteria may be applied to determine whether object penetration has
occurred, that is, whether the vertical measurement of at least one
object exceeds the vertical measurement of the OCS at the location
of the object. If the height or elevation of at least one object
exceeds the height or elevation of the OCS at the location of the
object, object penetration has occurred.
The flowchart continues with module 708 with the adjusting of the
missed approach OCS using missed approach design criteria if
necessary. The adjustment may be necessary if an object is
penetrating the OCS and no remedy exists to address the penetration
or to allow the use of a penetrated OCS. In one embodiment, the
adjustment of the OCS could be made by adopting a CG indicative of
real-time aircraft climb performance that has been computed using
one or more input factors 150. In an alternative embodiment, an
adjustment could be made through the use of an iterative process.
In an alternative embodiment, an adjustment could be made through
the use of a path construction function.
In an alternative embodiment, the adjustment of the missed approach
OCS could depend on a minimum obstacle clearance distance between
the penetrating object and the climb path at a corresponding
location of the penetrating object. The height or elevation of the
climb path could be vertically offset by the value of a minimum
obstacle clearance distance. The value of a minimum obstacle
clearance distance could be fixed or variable determined as a
function of one or more criteria by a manufacturer or end user. For
example, it may be determined as a function of alerting criteria
established for a TAWS system. For each penetrating object, if the
height or elevation of the object does not exceed the height or
elevation of the vertically offset climb path corresponding to the
location of the object, then the adjustment to the OCS may not be
necessary. In another embodiment, the adjustment of the OCS could
depend on both the adoption of an estimated aircraft climb
performance indicator as the CG and the use of the minimum obstacle
clearance distance.
The flowchart continues with module 710 with the modifying of the
applicable decision altitude data determined in module 612.
Applicability of the decision altitude data may depend on whether
the missed approach OCS was adjusted. If the missed approach OCS
was adjusted, then the modified applicable decision altitude data
may become the applicable decision altitude data of module 612 and
used in the generation of data representative of a final approach
procedure of module 614.
If a modification is made, it could be limited, where such
limitation could be based on final approach design criteria. For
example, the values of LTP(elev) and GPA of the glidepath may be
limited by final approach design criteria, where such limitation
could be based on the category of aircraft. Then, the flowchart
ends.
FIG. 16 depicts a flowchart 800 of an example of a third method for
generating procedure data used in an avionics system. The flowchart
begins with module 802 which could perform the same function as
disclosed in modules 602.
The flowchart continues with module 804 with the defining of a
flight path for a departure path. The departure path for a
departure procedure could be a climb path. A climb path may have a
constant CG. A departure path may comprise of one or more
ascertainable points. One point of a climb path may a LTP for the
opposite runway of take-off, and another point could be a waypoint
along the proposed flight path. One or more points could correspond
to existing waypoints contained in a published procedure, where the
waypoints may establish a specific location (e.g.,
longitude/latitude coordinate) and could be used to describe a
variety of fixes in a procedure including, but not limited to, RNAV
waypoints, ground-based NAVAIDs, navigation fixes defined using
ground-based NAVAIDs, and point(s) on a runway.
In one embodiment, data representative of an existing or published
procedure may be used to establish a departure path as embodied
herein. For instance, a CG of an existing departure procedure may
be used. In an embodiment disclosed herein, a climb path associated
with a departure flight path could be defined by at least one fix
of a published or established departure procedure. For example, the
location of one fix could be a designated end of the runway
("DER"); a location of a second fix could be an ascertainable
terminating altitude along the departure path. The height of the
first fix could be defined as a DER elevation, and the height of
the second fix could be determined as a terminating altitude as
determined by design criteria.
If an existing or published departure procedure has not been
established for the runway or is unavailable for use because of,
for example, a restriction based on a category of the aircraft,
alternative means may be employed to establish a climb path. In one
embodiment, a climb path may be derived through an iterative
process such as, but not limited to, the process discussed above.
In another embodiment, a climb path may be derived through a path
construction function. As discussed above, the employment of a path
construction function could produce a curved flight path. If a path
construction function is employed, the design criteria functions
applicable to a straight path could still be applied to a curved
path. For example, any distance measured along the curved path
could be used for the purpose of examining for object penetration.
Moreover, restrictions or limitations associated with a departure
path could apply to a curved path.
The flowchart continues with module 806 with the construction of an
OCS for a departure path. As discussed herein, the OCS may be
constructed using departure procedure design criteria. Design
criteria could include data representative of the climb path such
as, but not limited to, CG. Also, design criteria could include
navigation data representative of the runway and final approach
procedure information such as, but not limited to, DER location and
elevation.
The flowchart continues with module 808 with the examining of the
OCS for object penetration. Design criteria may be applied to
determine whether object penetration has occurred, that is, whether
the vertical measurement of at least one object exceeds the
vertical measurement of the OCS at the location of the object. If
the height or elevation of at least one object exceeds the height
or elevation of the OCS at the location of the object, object
penetration has occurred.
The flowchart continues with module 810 with the adjusting of the
OCS using design criteria if necessary. The adjustment may be
necessary if an object is penetrating the OCS and no remedy exists
to address the penetration or to allow the use of a penetrated OCS.
In one embodiment, the adjustment of the OCS could be made by
adopting a CG indicative of real-time aircraft climb performance
that has been computed using one or more input factors 150. In an
alternative embodiment, an adjustment could be made through the use
of an iterative process. In an alternative embodiment, an
adjustment could be made through the use of a path construction
function.
In an alternative embodiment, the adjustment of the OCS could
depend on a minimum obstacle clearance distance between the
penetrating object and the climb path at a corresponding location
of the penetrating object. The height or elevation of the climb
path could be vertically offset by the value of a minimum obstacle
clearance distance. The value of a minimum obstacle clearance
distance could be fixed or variable determined as a function of one
or more criteria by a manufacturer or end user. For example, it may
be determined as a function of alerting criteria established for a
TAWS system. For each penetrating object, if the height or
elevation of the object does not exceed the height or elevation of
the vertically offset climb path corresponding to the location of
the object, then the adjustment to the OCS may not be necessary. If
an adjustment is made, it could be limited.
The flowchart continues with module 812 with the generation of data
representative of a departure procedure. The procedure could
include a climb path passing through at least one fix. For example,
a climb path could pass through a fix associated with a terminating
altitude. The altitude of each fix could be determined using design
criteria.
As embodied herein, a departure procedure could be constructed with
a plurality of data. In one example, data representative of
distance information to a waypoint could be incorporated into the
procedure by computing the distance to the waypoint. In another
example, data representative of the vertical angle information of
the climb path could be incorporated into the procedure; if such
incorporation is made, it could be made to a CG having a value
other than a standard value. In another example, data
representative of path geometry could be incorporated into the
departure procedure including, but not limited to, defining the leg
types between the fix or fixes as a track to a fix ("TF") which a
known descriptor field commonly employed by an FMS. In another
example, data representative of altitude description information
could be incorporated into the final approach procedure to describe
a waypoint crossing characteristic appropriate for the
waypoint.
The flowchart continues with module 814 with the providing of data
representative of the departure procedure to at least one avionics
system. In one embodiment, the system could be an FMS. In another
embodiment, the system could be display units. Display units may
include, but are not limited to, a tactical display unit, a
strategic display unit, a HUD unit, or a display unit which may
display departure path information. As embodied herein, departure
procedure data could be used, in part or in whole, in the
generation of a flight route corridor image. In another embodiment,
the avionics system could be a vision system which generates an
image data set which represents the image displayed on a display
unit. Vision systems include, but are not limited to, SVS, EVS,
combined SVS-EVS, or combination thereof. As embodied herein,
departure procedure data could be included, in part or in whole, in
the generation of an image data set. As embodied herein, the image
represented the image data set could include an image of a flight
route corridor. Then, the flowchart ends.
It should be noted that the method steps described above could be
embodied in computer-readable media including, but not limited to,
computer instruction code. It shall be appreciated to those skilled
in the art that not all method steps must be performed, nor must
they be performed in the order stated. As embodied herein, the
actions that could be performed by an processor 170 are included as
method steps
As used herein, the term "embodiment" means an embodiment that
serves to illustrate by way of example but not limitation.
It will be appreciated to those skilled in the art that the
preceding examples and embodiments are exemplary and not limiting
to the scope of the present invention. It is intended that all
permutations, enhancements, equivalents, and improvements thereto
that are apparent to those skilled in the art upon a reading of the
specification and a study of the drawings are included within the
true spirit and scope of the present invention. It is therefore
intended that the following appended claims include all such
modifications, permutations and equivalents as fall within the true
spirit and scope of the present invention.
* * * * *
References